85 GSL-SE dies in turns when throttle applied
11-25-18, 09:28 AM
#1
No longer New
Thread Starter
85 GSL-SE dies in turns when throttle applied
Hi Guys! I'm a bit baffled. My GSL-SE is a bone stock example with 89,000 miles.I was forced to install new hi-flow cat from walker, but it passed California emissions with flying colors. In a straight line, car runs really strong all the way up the tach, no hiccups or dead spots at all. I changed out plugs, wires, cap, rotor, and coils (old ones were in the car since 2008) with OEM parts and set timing. All was well for about a week. Then, when turning left in second gear, engine dies when pressing accelerator. As long as I don't add throttle, all is well. Have eliminated loose connections and shorts as a possibilty, as all other electrics work just fine when it does this. Spent some quality time with my ohm-meter checking TPS (fine), coils(fine) and variable resistor(fine). BAC functioning as engine idles up when AC is running or lights are on. No hissing sounds. Idles smooth as glass at 800 RPM with no load. Now, when I change lanes (right or left) and add throttle it does the same thing, but ONLY when the wheel is turned off center. As soon as I straighten the wheel out, it's fine. Sometimes on a 1-2 upshift at 4k RPM, it will BACKFIRE as well. Not all the time and never when car is stationary and revved to 3500 RPM with abrupt, throttle release. Dashpot controlling decel just fine. I KNOW the problem is ignition (the car pulls harder above 4k than it does below), but I think I may have tossed too many variables in the equation when I did the full tune up. It's driving me NUTS! Any help is appreciated. I want my baby back!
11-25-18, 11:41 AM
#4
ancient wizard...
Did this problem exist before the tune up or was the tuneup the fix for the problem. When this happens does the engine die or just lose power as in if you pushed clutch in would it shut off? What is the tach doing while this is happening?
Can you duplicate the problem when the car is not moving,have you tried manipulating the wire harness at igniters,between them and ignition coils? Broken wire inside insulation?
Can't imagine any correlation between steering wheel straight and being turned other than some lateral G force working on a loose connection,or some now movement sensitive component.
Suggest you revisit TPS,did you sweep test the TPS thru full range from idle to wot. Do this engine cold and engine hot,particularly after an "event". Look for dropouts or glitches. Look closely at wires coming out of air temp sensor in dynamic chamber,test sensor against chart in FSM at different temps,cold to hot.
After doing the above,did you save all parts removed when doing tune up? You mention oem parts,is that MAZDA oem or some other "equivalent" part. Start reinstalling parts that were in place before your tuneup,one at a time,then test drive. You want to replace one part at a time as if you reinstall all original parts and it"fixes"problem,you won't know what the exact problem was. Start with leading coil,trailing coil(pay close attention to condition of all associated connectors) cap/rotor/wires then plugs. Look at plug wires closely,connectors specifically,ohm the wires out,pay attention to how they're routed. Are they touching anything,each other between cap and plugs. Examine insulator on plugs for cracking or carbon trails. Use of a plug socket without rubber insulator cushion or regular 13/16" deep socket can allow socket to be off center just enough to lightly crack or chip insulator on plug.
Be certain metal shield that covers pickup coils is seated properly,while in there check to be sure pickup coil wires are not broken. Have a quick look under car at fuel pump wire harness and connections at pump.
When is last time fuel filter was changed?If not recently do so and check contents by tapping filter onto paper towels,leave gas on towel to dry up and inspect what came out. Now would be a good time to pull off inlet hose on fuel pump and extract filter screen to examine for debris.
Remove air filter and check airbox for debris and air intake for critters. Check that air flow meter flap moves freely with no binding.
I worked on an SE that had a complaint of fluttering/loss of power around mid throttle and found the problem was caused by the red wire in leading pickup coil connector was broken at terminal but insulation was not and when vacuum advance pod advanced timing it would change the relationship of wire to connector. To test this i removed cap/rotor,leading/trailing igniters and probed pickup coil connectors at dist body with ohmmeter and got resistance reading then used vacuum pump to apply vacuum and watched ohmmeter and saw leading coil pickup resistance changed inconsistently but trailing did not. Manipulating red/green wires at pickup connector i could duplicate fluctuating resistance. Replaced pickups and problem did not return. Spent a fair amount of time diagnosing before i found this, first checking basics then checking each component in more detail. Diagnostics is really systematic elimination of individual components to isolate the one that is the cause of the fault.
Possible you built this problem in with a intermittent faulty component,it is possible to get a defective new part. Not as likely with a Mazda oe part as is possible with aftermarket parts but is still possible. Also possible to disturb a connection that has not been touched in 33 years or inadvertently break/damage a connector or wire.
Can you duplicate the problem when the car is not moving,have you tried manipulating the wire harness at igniters,between them and ignition coils? Broken wire inside insulation?
Can't imagine any correlation between steering wheel straight and being turned other than some lateral G force working on a loose connection,or some now movement sensitive component.
Suggest you revisit TPS,did you sweep test the TPS thru full range from idle to wot. Do this engine cold and engine hot,particularly after an "event". Look for dropouts or glitches. Look closely at wires coming out of air temp sensor in dynamic chamber,test sensor against chart in FSM at different temps,cold to hot.
After doing the above,did you save all parts removed when doing tune up? You mention oem parts,is that MAZDA oem or some other "equivalent" part. Start reinstalling parts that were in place before your tuneup,one at a time,then test drive. You want to replace one part at a time as if you reinstall all original parts and it"fixes"problem,you won't know what the exact problem was. Start with leading coil,trailing coil(pay close attention to condition of all associated connectors) cap/rotor/wires then plugs. Look at plug wires closely,connectors specifically,ohm the wires out,pay attention to how they're routed. Are they touching anything,each other between cap and plugs. Examine insulator on plugs for cracking or carbon trails. Use of a plug socket without rubber insulator cushion or regular 13/16" deep socket can allow socket to be off center just enough to lightly crack or chip insulator on plug.
Be certain metal shield that covers pickup coils is seated properly,while in there check to be sure pickup coil wires are not broken. Have a quick look under car at fuel pump wire harness and connections at pump.
When is last time fuel filter was changed?If not recently do so and check contents by tapping filter onto paper towels,leave gas on towel to dry up and inspect what came out. Now would be a good time to pull off inlet hose on fuel pump and extract filter screen to examine for debris.
Remove air filter and check airbox for debris and air intake for critters. Check that air flow meter flap moves freely with no binding.
I worked on an SE that had a complaint of fluttering/loss of power around mid throttle and found the problem was caused by the red wire in leading pickup coil connector was broken at terminal but insulation was not and when vacuum advance pod advanced timing it would change the relationship of wire to connector. To test this i removed cap/rotor,leading/trailing igniters and probed pickup coil connectors at dist body with ohmmeter and got resistance reading then used vacuum pump to apply vacuum and watched ohmmeter and saw leading coil pickup resistance changed inconsistently but trailing did not. Manipulating red/green wires at pickup connector i could duplicate fluctuating resistance. Replaced pickups and problem did not return. Spent a fair amount of time diagnosing before i found this, first checking basics then checking each component in more detail. Diagnostics is really systematic elimination of individual components to isolate the one that is the cause of the fault.
Possible you built this problem in with a intermittent faulty component,it is possible to get a defective new part. Not as likely with a Mazda oe part as is possible with aftermarket parts but is still possible. Also possible to disturb a connection that has not been touched in 33 years or inadvertently break/damage a connector or wire.
11-25-18, 11:42 AM
#5
meaning it happens when full and low ? gas slosh is a real issue, you could have a broken pickup tube in your tank
hey you're the one asking for help...
sounds like there's a uncovered wire somewhere that's moving left and right when you turn that's grounding out your power
From a stop can you turn the wheel left/right and slowly start to go forward or will it die right away ? if not, at what speed does it lose power? - id imagine as soon as the car starts to pull you to one side of the seat ?
hey you're the one asking for help...
sounds like there's a uncovered wire somewhere that's moving left and right when you turn that's grounding out your power
From a stop can you turn the wheel left/right and slowly start to go forward or will it die right away ? if not, at what speed does it lose power? - id imagine as soon as the car starts to pull you to one side of the seat ?
11-25-18, 02:00 PM
#6
84SE-EGI helpy-helperton
GSLSEforme covered this but briefly; it sounds to me like it's an electrical connection or wiring going to the fuel pump. The connector is inside the drivers side bin so check that, along with getting under the car and checking the wiring and ground as it goes to the fuel pump. No pump operation kills the car fast. I would venture a guess that when you turn, something or gravity pulls on the connector or wiring and causes a short, shutting off the fuel pump. If not there, check also under the drivers left foot wiring block, as there's a fuse for fuel pump with associated wiring.
if the car immediately returns to normal operation after the turn with you doing nothing but straightening out the steering, it supports my belief you have cornering forces being applied to a wiring harness or ground, causing the loss of power to the pump. Good luck, report back,
if the car immediately returns to normal operation after the turn with you doing nothing but straightening out the steering, it supports my belief you have cornering forces being applied to a wiring harness or ground, causing the loss of power to the pump. Good luck, report back,
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11-25-18, 04:20 PM
#8
No longer New
Thread Starter
Cannot repeat this behavior at rest. I can turn the wheel at idle in gear with clutch in or in neutral with clutch out and car runs normally even when I rev to 3500 rpm. (Not equipped with power steering) Car was running perfectly before the "tune up". I pitched all of the old parts. Tach reading normal. Trailing ignitor OK. I know where youre going with that. Had a 12A with bad trailing ignitor. Doesn't say anywhere in factory shop manual that fuel pump will shut off with no tach reading. Learned that the hard way. I will revisit TPS and see what it does when I turn with car in neutral and gas it a bit. Thanks for the pick up coil tip. I will look into this and let you know. Fuel delivery not an issue. Car runs strong in a straight line and pulls hard all the way up to redline, with ZERO hesitation or drop in power anywhere in the revband.
11-25-18, 04:23 PM
#9
No longer New
Thread Starter
It only does it when i'm on the throttle. Freakin wierd. NO sputter. Instant death. When I release throttle or straighten out the wheel all is well with the world again. I KNOW it's ignition, not fuel.
11-26-18, 04:54 AM
#10
I would venture a guess that when you turn, something or gravity pulls on the connector or wiring and causes a short, shutting off the fuel pump. If not there, check also under the drivers left foot wiring block, as there's a fuse for fuel pump with associated wiring.
if the car immediately returns to normal operation after the turn with you doing nothing but straightening out the steering, it supports my belief you have cornering forces being applied to a wiring harness or ground, causing the loss of power to the pump. Good luck, report back,
if the car immediately returns to normal operation after the turn with you doing nothing but straightening out the steering, it supports my belief you have cornering forces being applied to a wiring harness or ground, causing the loss of power to the pump. Good luck, report back,
no worries brother! we're all just here to help, we'll get it sorted
11-27-18, 08:30 AM
#11
84SE-EGI helpy-helperton
Note also that the Fuel Pump switch is located inside the Air Flow Meter, so when the Air Meter Door opens, it turns on the EFI Pump, so look around there for wiring issues, as well. The harness tends to get brittle with age, but I'm going to dissent from the group and suggest it's still fuel related, i.e., Pump is turning off mid corner.
Quick test: shunt a wire across the green EFI Test Plug by the AFM which forces the Fuel Pump to 100% operation and take it for a test drive around a few corners. If it fixes the problem, you found your culprit. Then, fix the connector or wiring and REMOVE your shunt or it will lead to flooding,...
Keep at it,
Quick test: shunt a wire across the green EFI Test Plug by the AFM which forces the Fuel Pump to 100% operation and take it for a test drive around a few corners. If it fixes the problem, you found your culprit. Then, fix the connector or wiring and REMOVE your shunt or it will lead to flooding,...
Keep at it,
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85ourx7 (01-14-19)
11-28-18, 09:07 AM
#13
84SE-EGI helpy-helperton
Given the longitudinal orientation of the AFM and flapper door (*Bosch L-Jetronic design), the door is counter balanced, front to back, but not side to side. The internal springs which close it are strong enough to prevent rapid door movement, and you also have the mass of incoming air to contend with. Turning left, this could cause the door to overtravel the path during WOT, but the 13b EFI doesn't draw that much air to be at that point unless the springs are weak or broken internally. Turning right would have the effect of trying to close the AFM air door, against incoming air. This also assumes that OP hasn't found some way to exceed 1.0G on lateral acceleration!
Point remaining that the switch for Fuel Pump operation at the AFM is Open without the engine running and circuit Closes (*turns on pump) as door as the door is moved even a tiny bit. If you listen closely, you can hear the switch close mechanically if you open the Air door with a stick, engine off.
This may be a good test, now that you mention it...
1. Key in ignition
2. Move to RUN position (*electric power is hot), not START
3. With Air Filter removed and air box open, insert pencil or chop stick into AFM
4. Push Air Door open slowly and completely to full throw. Fuel Pump and rail pressure will be heard.
If Fuel Pump or Pressure in the Fuel Rail stops, for any reason when manipulating the Air Door, it's a bad AFM. I'm still thinking it's a wiring harness getting pulled during cornering, though...
Point remaining that the switch for Fuel Pump operation at the AFM is Open without the engine running and circuit Closes (*turns on pump) as door as the door is moved even a tiny bit. If you listen closely, you can hear the switch close mechanically if you open the Air door with a stick, engine off.
This may be a good test, now that you mention it...
1. Key in ignition
2. Move to RUN position (*electric power is hot), not START
3. With Air Filter removed and air box open, insert pencil or chop stick into AFM
4. Push Air Door open slowly and completely to full throw. Fuel Pump and rail pressure will be heard.
If Fuel Pump or Pressure in the Fuel Rail stops, for any reason when manipulating the Air Door, it's a bad AFM. I'm still thinking it's a wiring harness getting pulled during cornering, though...
01-14-19, 03:18 PM
#14
No longer New
Thread Starter
Had some family issues that needed to be taken care of, but I'm back at it. TPS is smooth across entire range, resistance increasing smoothly with no dead spots all the way to WOT.
About the green test connector...which connections do I run a jumper across? There are 3 wires. The two vertical ones? (as I'm looking at directly at it of course). I'm willing to give it a shot. Had a little fuel leak where Hi pressure hose connects to injector pipe. I pulled intake off. installing new hoses and replacing o-rings, grommets, filters and pintle caps on injectors. Both injectors test at 1.9 Ohms of resistance, which is bang on. Noticed that there is no gasket between the two halves of the intake manifold. That one is on order as well. Let me know your thoughts. Thanks!
About the green test connector...which connections do I run a jumper across? There are 3 wires. The two vertical ones? (as I'm looking at directly at it of course). I'm willing to give it a shot. Had a little fuel leak where Hi pressure hose connects to injector pipe. I pulled intake off. installing new hoses and replacing o-rings, grommets, filters and pintle caps on injectors. Both injectors test at 1.9 Ohms of resistance, which is bang on. Noticed that there is no gasket between the two halves of the intake manifold. That one is on order as well. Let me know your thoughts. Thanks!
01-14-19, 04:58 PM
#15
ancient wizard...
The 3 wire connector at TPS throttle body area is not jumped. It is used with a low watt test light rig to precisely adjust tps position or a pair of multimeters. I like the 2 light test rig,mimics operation of original Mazda tps tester. Very easy to make one.
Sweep test i referred to in prior post has 2 parts. One checks resistance and the other tracks actual signal return voltage to ecu.
Have found more than a few defective tps sensors over the years sweeping the throttle slowly especially in the light cruise area of throttle position looking for intermittent dropouts/glitches/dead spots. The carbon wiper in tps wears here more than any other place in throttle travel.These will directly cause hiccups,intermittent loss of power and backfiring. Done with key on/engine off cold and hot.
The connector that LongDuck mentioned to jumper in previous post is also a green connector but is a two terminal and located at right inner fenderwell in proximity to air filter housing and adjustable potentiometer bolted to fender apron. Its purpose is to run fuel pump to pressurize system for pressure testing and for finding fuel leaks without needing to have car running. 1st,identify connector,make a short jumper wire with 1/4" male spade terminals on each end. Drive car to duplicate complaint,pull over,install jumper and repeat road test til failure. If car still acts up with jumper in place,contacts on switch in air flow meter can be ruled out as cause of problem. Don't leave jumper in place and continue to drive car as it circumvents circuitry that would shut off fuel flow in event of an accident.
Sweep test i referred to in prior post has 2 parts. One checks resistance and the other tracks actual signal return voltage to ecu.
Have found more than a few defective tps sensors over the years sweeping the throttle slowly especially in the light cruise area of throttle position looking for intermittent dropouts/glitches/dead spots. The carbon wiper in tps wears here more than any other place in throttle travel.These will directly cause hiccups,intermittent loss of power and backfiring. Done with key on/engine off cold and hot.
The connector that LongDuck mentioned to jumper in previous post is also a green connector but is a two terminal and located at right inner fenderwell in proximity to air filter housing and adjustable potentiometer bolted to fender apron. Its purpose is to run fuel pump to pressurize system for pressure testing and for finding fuel leaks without needing to have car running. 1st,identify connector,make a short jumper wire with 1/4" male spade terminals on each end. Drive car to duplicate complaint,pull over,install jumper and repeat road test til failure. If car still acts up with jumper in place,contacts on switch in air flow meter can be ruled out as cause of problem. Don't leave jumper in place and continue to drive car as it circumvents circuitry that would shut off fuel flow in event of an accident.
Last edited by GSLSEforme; 01-14-19 at 05:01 PM.
01-15-19, 07:53 PM
#16
Senior Member
there is a in tank filter .. u could drop the tank and check for sediment .... but before u do that check the fuel pump there is a small cone shaped filter inserted in the pump...this lil filter has caused headaches for many SE guys.... good luck
01-21-19, 05:24 PM
#18
No longer New
Thread Starter
Fuel injectors rebuilt (o-rings, grommets, micro filters and pintle caps replaced), fuel pressure regulator replaced. It runs better and no more fuel leak. The green test connector next to the air filter housing in my car has THREE connections. Two vertical and one horizontal underneath. There is another connector that has a rubber boot around it that has two prongs, but it's NOT green. Dont want to jump any connections till I'm sure which ones are correct. Going to see if it still dies in turns tomorrow. At least its running now! Thanks for all the tips! It is not taken for granted.
01-25-19, 07:26 PM
#19
No longer New
Thread Starter
Update:
AFM tests good. Fuel pump engages with ignition on/engine off with slightest touch on the door and stays on throughout the full sweep. New TPS installed. Still does exactly the same thing. runs perfect in a straight line. Pulls HARD all the way up to 7K, no fade anywhere, unless the wheel is turned. Going to replace fuel filter just because, but it would fade under high load/RPM if there was a flow/pressure issue, regardless of steering wheel position. Anyone have any feedback about test connectors? My green one by the air filter housing has THREE female prongs, but there is a white 2 prong connector with a rubber boot around it as well. I want to try to jump the 2 terminals Long Duck mentioned. It dies when wheel is turned to the LEFT even slightly, but only when throttle is applied, even when cruise control is engaged. But not at rest. Mystifying! Annoying!
AFM tests good. Fuel pump engages with ignition on/engine off with slightest touch on the door and stays on throughout the full sweep. New TPS installed. Still does exactly the same thing. runs perfect in a straight line. Pulls HARD all the way up to 7K, no fade anywhere, unless the wheel is turned. Going to replace fuel filter just because, but it would fade under high load/RPM if there was a flow/pressure issue, regardless of steering wheel position. Anyone have any feedback about test connectors? My green one by the air filter housing has THREE female prongs, but there is a white 2 prong connector with a rubber boot around it as well. I want to try to jump the 2 terminals Long Duck mentioned. It dies when wheel is turned to the LEFT even slightly, but only when throttle is applied, even when cruise control is engaged. But not at rest. Mystifying! Annoying!
01-25-19, 07:29 PM
#20
No longer New
Thread Starter
Update:
AFM tests good. Fuel pump engages with ignition on/engine off with slightest touch on the door and stays on throughout the full sweep. New TPS installed. Still does exactly the same thing. runs perfect in a straight line. Pulls HARD all the way up to 7K, no fade anywhere, unless the wheel is turned. Going to replace fuel filter just because, but it would fade under high load/RPM if there was a flow/pressure issue, regardless of steering wheel position. Anyone have any feedback about test connectors? My green one by the air filter housing has THREE female prongs, but there is a white 2 prong connector with a rubber boot around it as well. I want to try to jump the 2 terminals Long Duck mentioned. It dies when wheel is turned to the LEFT even slightly, but only when throttle is applied, even when cruise control is engaged. But not at rest. Mystifying! Annoying!
AFM tests good. Fuel pump engages with ignition on/engine off with slightest touch on the door and stays on throughout the full sweep. New TPS installed. Still does exactly the same thing. runs perfect in a straight line. Pulls HARD all the way up to 7K, no fade anywhere, unless the wheel is turned. Going to replace fuel filter just because, but it would fade under high load/RPM if there was a flow/pressure issue, regardless of steering wheel position. Anyone have any feedback about test connectors? My green one by the air filter housing has THREE female prongs, but there is a white 2 prong connector with a rubber boot around it as well. I want to try to jump the 2 terminals Long Duck mentioned. It dies when wheel is turned to the LEFT even slightly, but only when throttle is applied, even when cruise control is engaged. But not at rest. Mystifying! Annoying!
01-25-19, 07:54 PM
#21
This may be a long shot ---I had an intermittent hard starting issue with my 85 GSL-SE. Replaced ignitors, plugs, etc. I finally cleaned the ignitor connectors and terminals with Corrosion X and it solved the problem. You might have an intermittent electrical contact issue somewhere.
01-26-19, 12:20 AM
#22
84SE-EGI helpy-helperton
There are 2 connectors in that area.
2-Terminal, Rubber Boot = Fuel Pump Pressure Test connector. THIS is the one you should be shorting to run the pump.
3-Terminal, No Boot = Throttle Position Sensor adjustment plug.
As mentioned prior, you likely have a short going to your fuel pump which only occurs when a portion of the wiring harness is pulled or tugged by either the action of the momentum of the car in a left turn, or the harness being pulled around by the steering wheel shaft. Start at the Fuel Pump under the car and work your way forward until you find bare wires, or a harness pulled taut that would cause a short. This assumes that you're losing fuel pressure and not spark (*ignitors, coils, white lead to ECU from Trailing Coil, etc...). Have at it, and be patient,
3-Terminal, No Boot = Throttle Position Sensor adjustment plug.
As mentioned prior, you likely have a short going to your fuel pump which only occurs when a portion of the wiring harness is pulled or tugged by either the action of the momentum of the car in a left turn, or the harness being pulled around by the steering wheel shaft. Start at the Fuel Pump under the car and work your way forward until you find bare wires, or a harness pulled taut that would cause a short. This assumes that you're losing fuel pressure and not spark (*ignitors, coils, white lead to ECU from Trailing Coil, etc...). Have at it, and be patient,
03-08-19, 03:00 PM
#23
84SE-EGI helpy-helperton
Commiserating with my own electrical gremlins, was curious if this got sorted out and what the final cause was determined to be...? Hope you fixed it,
03-16-19, 06:47 AM
#24
Rotary Enthusiast
Only a comment. Man!!! You got the best in LongDuck and Gslseforme in your corner. And!! From the length of their comments you can tell they really really care. It’s one of the most unique characteristics of this club versus the Boingers. These ARE the Rotary gods and they are always “on it”! Make sure you let these guys know the outcome either way. They earned it. Thank you guys. Gslseforme has helped me a number of times. We’re blessed to have them. Always say Thank You!
03-16-19, 10:31 AM
#25
84SE-EGI helpy-helperton
Everybody contributes something,
And I echo your sentiment that the Rotary Gods do favor the 1st Gen forum, because these guys have the most experience owning and driving these cars from the 80's!
Having GSLSEforme as a past Mazda technician has been a real blessing, along with the guys who race that help with configurations that just work and finding the weaknesses before we do on the street - the forum is an amazing collection of people.
Having GSLSEforme as a past Mazda technician has been a real blessing, along with the guys who race that help with configurations that just work and finding the weaknesses before we do on the street - the forum is an amazing collection of people.
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85ourx7 (12-17-19)