ARG! Engine swap wont go!
08-05-03, 04:41 PM
#1
FD > FB > FC
Thread Starter
ARG! Engine swap wont go!
Guys I'm completely out of ideas for my engine swap. What I did, is I have a 85 rx-7 gs, and I swapped in a S5 N/A motor. I swapped in the complete longblock, fuel injection and everything. The only wierd thing I had to do was modify a 12a front cover to accept the 89 OMP.
But anyway, I am actually using an S4 for the block itself, but I have all the manifolds and everything else from an S5. I blocked off the port air in the intake manifold and everything.
The thing will not IDLE!! No matter what i do, the thing simpily will not idle. When I start it after a crank or two, it catches for a second and then dies if I dont have my foot on the gas. If I put my foot on the gas it revs fine, but runs really really rough below 2,000 RPM. It sounds like its running lean as hell to me. I can move the revs thoughout 800-2000 rpm, but once I let my foot off the gas it dies. The thing also backfires every now and then.
I have checkd my timing, I even bought a racing beat underdrive pulley to make sure because the timing mars on my origional pulley were incorrect. (the old pulley was from my old 12a)
Theres no way there can be a vacuum leak either, every, manifold is sealed. And all the vacuum lines are new and were replaced one at a time and I just spent a day checking them.
The wiring is the stock 89 harness, stripped of everything that doesnt relate to the engine (headlights etc.) HOWEVER, my clutch switch is not working, and I do not have a neutral switch. I also dont have the connector in the water pump housing connected. (not the water thermosensor, the one that triggers the A/C fan)
I do not have my oil pressure guage set up. Is it possible that a lack of oil pressure could be causing my problem?
The last thing I can think of, is the EGR port. I bought a block off plate for it, and used the stock gasket. However I didnt worry about the little hole thing at the exhaust ports. The hole is actually covered by a gasket, because I am using a GSL-SE exhaust manifold, so the GSL-SE gasket covers the EGR hole.
I'm stumped!!! What the hell could be causing this?
But anyway, I am actually using an S4 for the block itself, but I have all the manifolds and everything else from an S5. I blocked off the port air in the intake manifold and everything.
The thing will not IDLE!! No matter what i do, the thing simpily will not idle. When I start it after a crank or two, it catches for a second and then dies if I dont have my foot on the gas. If I put my foot on the gas it revs fine, but runs really really rough below 2,000 RPM. It sounds like its running lean as hell to me. I can move the revs thoughout 800-2000 rpm, but once I let my foot off the gas it dies. The thing also backfires every now and then.
I have checkd my timing, I even bought a racing beat underdrive pulley to make sure because the timing mars on my origional pulley were incorrect. (the old pulley was from my old 12a)
Theres no way there can be a vacuum leak either, every, manifold is sealed. And all the vacuum lines are new and were replaced one at a time and I just spent a day checking them.
The wiring is the stock 89 harness, stripped of everything that doesnt relate to the engine (headlights etc.) HOWEVER, my clutch switch is not working, and I do not have a neutral switch. I also dont have the connector in the water pump housing connected. (not the water thermosensor, the one that triggers the A/C fan)
I do not have my oil pressure guage set up. Is it possible that a lack of oil pressure could be causing my problem?
The last thing I can think of, is the EGR port. I bought a block off plate for it, and used the stock gasket. However I didnt worry about the little hole thing at the exhaust ports. The hole is actually covered by a gasket, because I am using a GSL-SE exhaust manifold, so the GSL-SE gasket covers the EGR hole.
I'm stumped!!! What the hell could be causing this?
08-05-03, 06:36 PM
#2
Former Moderator. RIP Icemark.
sounds like the timing is off (you are aware that the spark plug holes are placed different between a S4 and S5, so the S5 'puter uses slightly altered timing) and that you have a vac leak.
08-05-03, 06:39 PM
#3
FD > FB > FC
Thread Starter
Oh really? Now this I did not know. Is there anyway I can compinsate for this?
Oh and one last thing I dont have my relief silencer plugged into my acv, I dont think it make a difference, just making sure.
Oh and one last thing I dont have my relief silencer plugged into my acv, I dont think it make a difference, just making sure.
08-06-03, 04:15 PM
#5
wHiTe kNiGhT
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ya i have the same exact problems, my friend tells me its a vaccum leak but i dont get how either, everything is new an tight. it might be a vaccum leak but i really doubt it. we couldnt check the timing because the car would only idle at 2k or more or else it would jus idle like ****, one thing i did notice was that after driving the car i put 150miles on it an it will idle once its warm, i can get it to idle around 1.2krpm but it will jump around, it wont idle good at all, it might be timing or vaccum im not sure yet, but i would like to know what happens to u, once u fix ur timing or do anything else to fix this idle problem.
08-06-03, 04:16 PM
#6
Former Moderator. RIP Icemark.
Relief silencer won't make any difference.
I am not sure on what can be done on the timing change (or if that is exactly the problem)... why are you using a S5 harness and ECU with a S4 engine?
I am not sure on what can be done on the timing change (or if that is exactly the problem)... why are you using a S5 harness and ECU with a S4 engine?
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08-06-03, 04:47 PM
#8
FD > FB > FC
Thread Starter
well, I cant get a neutral switch because my treansmission doesnt have one. My transmission is a 81-83, and everything before 84 did not have a neutral switch on it. Sounds like i need to get a GSL-SE tranny.
Now couldnt I just rig up something to fooling the computer into thinking its never in neutral?
As far as the S5 harness on the s4 engine, basically what happened was I had inteneded on putting a s5 engine in there. I got everything but the bare block itself. The block was supposed to be purchased from the shop that did my rebuild. However the owner explained that it wouldn't matter if I used a s4 or s5 block as long as I blocked off the port air.
He also said that most of the power gains from s4 to s5 were from the better designed intake manifold, NOT the higher compression rotors. Also he said that he has several s4 blocks allready, and he could get an s5 tomorrow or in 3 months, ya never know.
Since I was on a time crunch at the time i went ahead with using the S4 block.
Even if the S5 ecu is timed differently, I wouldnt think that it would make enough difference to prevent the thing from idleing.
Now the other thing is cant I set the thing to idle at 2000 or so? Or even 1500? If I hit the throttle steady enough to keep it at 1500, it runs pretty smooth, but once I take my foot of the gas it dies. I have the idle speed screw turned up all the way (top of the throttle body The screw is turned in counter clockwise.) And I grounded the one wire green connector that you have to ground when you make idle adjustments.
Is there anyway I can force this thing to idle? I'm not too worried about it idleing around 800 because these are used rotor housings, so it shouldnt idle right for the first hundred miles or so.
The idle speed adjustment screw seems to do absolutely nothing... what gives?
Now couldnt I just rig up something to fooling the computer into thinking its never in neutral?
As far as the S5 harness on the s4 engine, basically what happened was I had inteneded on putting a s5 engine in there. I got everything but the bare block itself. The block was supposed to be purchased from the shop that did my rebuild. However the owner explained that it wouldn't matter if I used a s4 or s5 block as long as I blocked off the port air.
He also said that most of the power gains from s4 to s5 were from the better designed intake manifold, NOT the higher compression rotors. Also he said that he has several s4 blocks allready, and he could get an s5 tomorrow or in 3 months, ya never know.
Since I was on a time crunch at the time i went ahead with using the S4 block.
Even if the S5 ecu is timed differently, I wouldnt think that it would make enough difference to prevent the thing from idleing.
Now the other thing is cant I set the thing to idle at 2000 or so? Or even 1500? If I hit the throttle steady enough to keep it at 1500, it runs pretty smooth, but once I take my foot of the gas it dies. I have the idle speed screw turned up all the way (top of the throttle body The screw is turned in counter clockwise.) And I grounded the one wire green connector that you have to ground when you make idle adjustments.
Is there anyway I can force this thing to idle? I'm not too worried about it idleing around 800 because these are used rotor housings, so it shouldnt idle right for the first hundred miles or so.
The idle speed adjustment screw seems to do absolutely nothing... what gives?
08-07-03, 10:08 AM
#11
HAILERS
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How about pulling the dynamic chamber off again??? And taking a look at the fuel injectors. The grommets on the bottom of the injectors should be pliable/soft. If the old years old ones were used maybe its leaking at the injectors where they meet the block.
Or don't remove the manifold. Just spray starter fluid down towards the injectors and see if there is an audible difference in the rpms. I'd pull the manifold myself since there is no real idle to deal with.
While there, block off the EGR.
Cap off the vac line going to the booster also.
Cap off all three vac lines on the front of the throttle body plus the ones on the back of the throttle body.
Then see if that makes a difference.
I vote for bad grommets at the bottom of the fuel injectors.
Or don't remove the manifold. Just spray starter fluid down towards the injectors and see if there is an audible difference in the rpms. I'd pull the manifold myself since there is no real idle to deal with.
While there, block off the EGR.
Cap off the vac line going to the booster also.
Cap off all three vac lines on the front of the throttle body plus the ones on the back of the throttle body.
Then see if that makes a difference.
I vote for bad grommets at the bottom of the fuel injectors.
08-07-03, 10:42 AM
#12
Seduced by the DARK SIDE
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I like HAILERS theory on the injector insulators. Many have been teased by that problem. I just sealed mine with a small O ring above the insulator ring.
On the neutral switch - The signal to pin 1R is grounded in neutral and open in gear - so just leave it open.
The 5th-Reverse switch signal to 1T is open in 5 or R, and grounded in 1-4.
So you may want to ground it.
On the neutral switch - The signal to pin 1R is grounded in neutral and open in gear - so just leave it open.
The 5th-Reverse switch signal to 1T is open in 5 or R, and grounded in 1-4.
So you may want to ground it.
08-07-03, 04:59 PM
#13
FD > FB > FC
Thread Starter
ur gonna love this, all the fuel injector o-rings and grommets are brand new.
The EGR is allready blocked off, I got the block off plate from mazdatrix.
As for the old tranny, I changed my car from a auto to a manual at the amse time I did the engine swap. The 83 tranny is all I could find at the time, and they are allmost the same as the 84-85 ones.
Heres something that I think may be use full. Everyday when I try to start the car, it wont even think about starting unless I start it first with the Fuel pump shorted out (the way you prime the fuel system). After that it will start, but it wont catch without me constantly moving the gas pedal.
The TPS is out of adjustment, but as far as I'm aware I should be getting a crappy idle at least. I'm going to o out and get the stuff for the 2 led method of calibrating the TPS this evening. However, that doesnt explain how hard to start it is.
I'm gonna try capping off all the vacuum stuff today too.
Any ideas?
The EGR is allready blocked off, I got the block off plate from mazdatrix.
As for the old tranny, I changed my car from a auto to a manual at the amse time I did the engine swap. The 83 tranny is all I could find at the time, and they are allmost the same as the 84-85 ones.
Heres something that I think may be use full. Everyday when I try to start the car, it wont even think about starting unless I start it first with the Fuel pump shorted out (the way you prime the fuel system). After that it will start, but it wont catch without me constantly moving the gas pedal.
The TPS is out of adjustment, but as far as I'm aware I should be getting a crappy idle at least. I'm going to o out and get the stuff for the 2 led method of calibrating the TPS this evening. However, that doesnt explain how hard to start it is.
I'm gonna try capping off all the vacuum stuff today too.
Any ideas?
Last edited by hornbm; 08-07-03 at 05:10 PM.
08-07-03, 05:17 PM
#14
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try opening the throttle stop screw some, and check the timing while you have your foot on the throttle to keep it running, you should be able to see the timing marks on the pully but the won't be lined up becuase the engine speed is higher than idle, so the timing marks should be no more than 1 inch to the left of pointer (around 1500 to 2000 rpms), if its to the right of it or more than 1 inch to the left you'll need to restab the CAS
08-08-03, 04:17 AM
#16
Originally posted by hornbm
As for the old tranny, I changed my car from a auto to a manual at the amse time I did the engine swap. The 83 tranny is all I could find at the time, and they are allmost the same as the 84-85 ones.
As for the old tranny, I changed my car from a auto to a manual at the amse time I did the engine swap. The 83 tranny is all I could find at the time, and they are allmost the same as the 84-85 ones.
but damn you gotta love those short gears...
Originally posted by hornbm
Heres something that I think may be use full. Everyday when I try to start the car, it wont even think about starting unless I start it first with the Fuel pump shorted out (the way you prime the fuel system). After that it will start, but it wont catch without me constantly moving the gas pedal.
Heres something that I think may be use full. Everyday when I try to start the car, it wont even think about starting unless I start it first with the Fuel pump shorted out (the way you prime the fuel system). After that it will start, but it wont catch without me constantly moving the gas pedal.
Originally posted by hornbm
The TPS is out of adjustment, but as far as I'm aware I should be getting a crappy idle at least. I'm going to go out and get the stuff for the 2 led method of calibrating the TPS this evening. However, that doesnt explain how hard to start it is.
The TPS is out of adjustment, but as far as I'm aware I should be getting a crappy idle at least. I'm going to go out and get the stuff for the 2 led method of calibrating the TPS this evening. However, that doesnt explain how hard to start it is.
this may sound stupid, but have you checked like 2412 times that your AFM is connected? my car will start without it connected (its a bitch to start) and i can get it to stay running around 1500-2000 rpms but its real real rough. i only know this because i've left the ****** unplugged so many times and tried to start it...
thats probably not it, but just a though.
go set your TPS, block off all the vacuum stuff, *try* to check the timing, and get back to us.
Last edited by jacobcartmill; 08-08-03 at 04:22 AM.
08-08-03, 04:20 AM
#17
Originally posted by BlackRx7
try opening the throttle stop screw some, and check the timing while you have your foot on the throttle to keep it running, you should be able to see the timing marks on the pully but the won't be lined up becuase the engine speed is higher than idle, so the timing marks should be no more than 1 inch to the left of pointer (around 1500 to 2000 rpms), if its to the right of it or more than 1 inch to the left you'll need to restab the CAS
try opening the throttle stop screw some, and check the timing while you have your foot on the throttle to keep it running, you should be able to see the timing marks on the pully but the won't be lined up becuase the engine speed is higher than idle, so the timing marks should be no more than 1 inch to the left of pointer (around 1500 to 2000 rpms), if its to the right of it or more than 1 inch to the left you'll need to restab the CAS
i think the timing may be a bit erratic to check legibly... he says he can get the engine running somewhat smooth at 2000 rpms, but it has to be pretty damn smooth to get an accurate reading with a regular ole inductive timing gun, not to mention the mark is gonna be way off anyways since he's at 2k rpms.
08-08-03, 05:05 PM
#20
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Originally posted by Icemark
sounds like the timing is off (you are aware that the spark plug holes are placed different between a S4 and S5, so the S5 'puter uses slightly altered timing) and that you have a vac leak.
sounds like the timing is off (you are aware that the spark plug holes are placed different between a S4 and S5, so the S5 'puter uses slightly altered timing) and that you have a vac leak.
Timing is based upon the position of the eccentric shaft, not the position of the spark plugs.
The change is position alters where the flame front propogates for a slightly more efficient burn, not for any advance in timing.
We know this is true due to the split timing between the leading and trailing plugs. Since they are in physically different spots, if the timing were rotor-position based, firing them at identical moments would provide different timing, yet we know they are eccentrically split by 15 degrees.
The eccentric shafts, keys, and drive gears are identical for S4's and S5's, and the pulley marks match up in identical positions.
It is the same thing as moving a spark plug in a head in a piston engine: some have the plug at the very top of the combustion chmaber, and many older technology place them at the sides. Position does not alter timing, merely where combustion begins.
Plug position is about where in the combustion chamber the combustion begins, timing is about the shape of the cumbustion chamber.
Common myth, but not the problem here. Most likely just a simple vacuum leak.
08-08-03, 11:03 PM
#21
FD > FB > FC
Thread Starter
ok, I've got the idle speed screw adjusted all the way up to allow the highest possible idle, and it still wont idle. I grounded the test connector too.
Someone said it may be running to rick to idle at the low RPMs. I'm thinking its just the oposite. I think its running really lean on account of the plugs keep fouling. (not very bad though.
As for the timing, I have a racing beat under drive pulley, so I know my timing is ok.
I also just checked the AFM, and its plugged in allright. I'm really thinking a vacuum leak, but WHERE?!?! This is annoying as hell!
Judging by how ruff it runs, id say it has to be a pretty big leak, but I just dont see where that big of a leak could be comming from.
The TPS is deffinately a problem, and the tesing methods dont seem to make any sence. The let lights dont work, so I'm gonna ohm it out.
Also this rebuild was done with used rotor housings so that isnt helping.
Last thing is that test connector you have to ground to make idle adjustments doesnt seem to do anything! I've even touched it to the negative battery terminal and it still doesnt do anything.
Someone said it may be running to rick to idle at the low RPMs. I'm thinking its just the oposite. I think its running really lean on account of the plugs keep fouling. (not very bad though.
As for the timing, I have a racing beat under drive pulley, so I know my timing is ok.
I also just checked the AFM, and its plugged in allright. I'm really thinking a vacuum leak, but WHERE?!?! This is annoying as hell!
Judging by how ruff it runs, id say it has to be a pretty big leak, but I just dont see where that big of a leak could be comming from.
The TPS is deffinately a problem, and the tesing methods dont seem to make any sence. The let lights dont work, so I'm gonna ohm it out.
Also this rebuild was done with used rotor housings so that isnt helping.
Last thing is that test connector you have to ground to make idle adjustments doesnt seem to do anything! I've even touched it to the negative battery terminal and it still doesnt do anything.
08-08-03, 11:49 PM
#22
The mystery of the prize.
You have S5 manifolds on a S4 block, your vacuum leak is likely due to this. The rear S4 housing interferes with the S5 UIM, you have to grind some material off to make it mount properly. If you have not ground anything, you have a vacuum leak.
08-09-03, 01:46 AM
#23
Originally posted by pengarufoo
You have S5 manifolds on a S4 block, your vacuum leak is likely due to this. The rear S4 housing interferes with the S5 UIM, you have to grind some material off to make it mount properly. If you have not ground anything, you have a vacuum leak.
You have S5 manifolds on a S4 block, your vacuum leak is likely due to this. The rear S4 housing interferes with the S5 UIM, you have to grind some material off to make it mount properly. If you have not ground anything, you have a vacuum leak.
interesting... i did not know this.
08-10-03, 03:33 PM
#24
FD > FB > FC
Thread Starter
Thankfully, I did know this. I did **** poor job a grinding it too, but my autoshop teacher said it looked ok when I did it.
Even though, I dont have any idea why that would cause a vacuum leak if I didnt grind it down.
Anyway heres an update!
I decieded to rig up a led to the check engine light terminal on the ecu (FB's dont have a check engine light) so that way I could find out if the ECU was letting out any error codes. Its nice to see a company that lets you retrive the codes for once WITHOUT the stupid code checker.
Anyway, the thing spat out two codes. One was for the Waterthermo sensor, and the other was for the Fuel Pump Resistor Relay.
For the water thermosensor, I'm not exactly sure what is causing this. I just refilled my cooling system so I'm sure that bubbles in the coolant could cause the sensor to act up. Or it *might* be because I dont have that additionly black one pin connector on the water pump housing hooked up. If I remember right its for triggering the fan if the A/C goes on or something. Then there is allways the possibility of the sensor being bad, or even more likely some of the wiring in that 14 year old harness has gone bad.
The fuel pump resistor relay has got me confused. The way I rigged up the fuel system was I ran a trigger line to the circuit opening relay, and the two leads from the fuel pump resisor relay that go to the fuel pump, I cut and put some new wires on there to go to my inline fuel pump. I just mergerd both of the wires into one wire and connected that to the positive terminal of the fuel pump. (FB's have an inline pump instead of an intank one, and I'm using a GSL-SE fuel pump)
Does anybody know exactly what could be doing this?
Even though, I dont have any idea why that would cause a vacuum leak if I didnt grind it down.
Anyway heres an update!
I decieded to rig up a led to the check engine light terminal on the ecu (FB's dont have a check engine light) so that way I could find out if the ECU was letting out any error codes. Its nice to see a company that lets you retrive the codes for once WITHOUT the stupid code checker.
Anyway, the thing spat out two codes. One was for the Waterthermo sensor, and the other was for the Fuel Pump Resistor Relay.
For the water thermosensor, I'm not exactly sure what is causing this. I just refilled my cooling system so I'm sure that bubbles in the coolant could cause the sensor to act up. Or it *might* be because I dont have that additionly black one pin connector on the water pump housing hooked up. If I remember right its for triggering the fan if the A/C goes on or something. Then there is allways the possibility of the sensor being bad, or even more likely some of the wiring in that 14 year old harness has gone bad.
The fuel pump resistor relay has got me confused. The way I rigged up the fuel system was I ran a trigger line to the circuit opening relay, and the two leads from the fuel pump resisor relay that go to the fuel pump, I cut and put some new wires on there to go to my inline fuel pump. I just mergerd both of the wires into one wire and connected that to the positive terminal of the fuel pump. (FB's have an inline pump instead of an intank one, and I'm using a GSL-SE fuel pump)
Does anybody know exactly what could be doing this?
08-10-03, 04:46 PM
#25
FD > FB > FC
Thread Starter
Too late to edit so I'll add this on.
I forgot to mention that I do not have the air injection line to my cat hooked up becuase I hollowed out my cat. That line has a one way check valve, so I'm wondering if leaving it open is makming a vacuum leak.
I forgot to mention that I do not have the air injection line to my cat hooked up becuase I hollowed out my cat. That line has a one way check valve, so I'm wondering if leaving it open is makming a vacuum leak.