I have a 1984 GSLSE and for some reason or another it just feels....slower.

When i first got the car it was pretty quick but one day i feel like I just lost a lot of power for some reason. The car has about 250,000 miles on it with headers, midpipe, and exhaust. Does anyone have an idea as to what I should check up on?

Oh yeah, and it also has a rebuilt engine with only 5000 miles on it so the engine is relatively new.

 

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no really though, check your fuel filter?

 

I had a similar problem in my car last year, the problem was that the leading ignitor went south... It doesn't hurt to go over your spark plug wires with a timing light and make sure that you are getting spark to all the plugs and that your timing is good.

 

Change your fuel filter if you haven't yet...

 

Spark and fuel delivery, everytime

 

I Had that same problem. I finally figured it out. I was driving a twin turbo, then I got in my N/A and felt like I was driving a go-kart!

 

LOL....

thanks for the spark and fuel filter suggestions, I'll look into it right away.

 

Your rotor seals could be getting loaded with carbon and sticking a little, causing you to lose a little compression. If this is happening, it is likely a tuning issue. Check (preferably change) plugs and change fuel filter, change oil, air filter, ect.

EDIT: I just read over the part about it happening all of a sudden. This leads me to believe that something may have gone wrong. I need more information. Does the car still run smoothly? If not, could you describe how it runs? Also, had the car been sitting for several days before you noticed that it was slower? There are alot of variables but if you give some more info I can help narrow it down.

 

The car runs smoothly, it just feels like it has a lot less power than before. The thing is, the motor is relatively new (rebuilt 5000 miles ago) with new parts but the car has almost 250k on the chassis, so a lot of other parts are old. The car felt slower after sitting for a few weeks.

 

Stuck brake dragging? Parking brake not releasing?

 

how would one check and correct if the breaks are not properly releasing?

 

jack it up...then put it on stands, take the wheels off and you could probably tell by spinning the brake discs

 

If the brakes were dragging, wouldn't there be noise coming from the wheels? If so, that would be noticeable...

 

put it in nuetral, and give it a shove. If it doesn't go anywhere then you have a stuck brake.

 

nah, i've pushed the car several times, it moves fine...

 

Check fuel filter and leading spark as mentioned. Also check the operation of the 5/6th ports.

Mazda used these additional ports that when closed, help low end torque, they then open under exhaust backpressure to help top end. They are located in the lower intake manifold. There are two accuators with rods connected. You should be able to push down on the rods and have them move. Sometimes carbon build up will keep them from working. There should also be a small vacuum hose that comes off the back of thelower intake manifold. This normally connects into the larger line form the air pump and ACV which then goes to the main cat. Make sure this line is still in place without any hole or cracks. The small line is what feeds the exhaust backpressure to the accuators and cause the 5/6 ports to open.

 

it was the leading ignition thanks guys.

It seems i need a new ignitor, distributor cap, and rotor for the distributor cap.

Thanks for all the help

 

I'm having a similar problem with my '82. It's my daily driver. One morning the performance went south! The car would barely climb hills. I limped it home, and haven't had any luck getting her back upto par.

Starts and runs fine, simply won't move with any enthusiasm! I've been digging through the archives looking for ideas...

 

This was a good trouble shooting thread. I just got my S3 last week after owning an s1 years back. I expected more umph out of the S3. I know my rotor is worn but i will also check my entire ignition system. I did not expect the rotor and coils to hurt performance that much.

Live and learn.

Gotta love the net and forums like this one. I wish this had been available 14 years ago when I built the S1.

 

This is an interesting thread and I think my troubles will add to it.

1984 GSL-SE

My daughter was driving the car and is had a sudden loss of power. She had it towed home and it sat for a few days. I drove it and it worked as well as before. I drove it some more and suddenly it had a loss of power. I mean way low. Barely able to pull away from a stop sign, pedal to the floor loss of power.

Diagnostic trail:
1. I waited until the next day and it ran normal again. Thinking it was a leading ignition problem, i disconnected the leading igniter and drove it. Definitely low on power, but more than in the failure mode.

2. Swapped the leading and trailing igniters. Drove and it worked as always. After a few miles, the sudden loss of power reoccured. Limped home, second gear, 45 mph, 6K rpm.

3. While in the failure mode, disconnected T2 and L2 spark wires, no change. Then disconnected T1 and L1, engine stopped. Aha, seems to be the rotor 2 is not firing.

4. Pulled out T2 spark plug and turned over. Nice psst, psst, psst. Good compression. I didn't use a pressure gauge.

5. Inserted a fuel pressure guage. It varied between 30 psi to 38 psi depending on RPMs and acceleration. It has a new fuel filter.

6. As well as I could, I couldn't hear any fuel injectors, I tried to touch the injector under the UIM, I think I felt it and felt like it was clicking. I think. I touched wires and vacuum and whatever. No changes in performance. Probably a non-test, but getting desperate.

At this point I believe rotor 2 isn't getting fuel. I don't know if it is the injector or the ECU. I had the UIM and DC off about a month ago and the fuel patterns on the injectors looked good. Considering the previous owner reversed battery polarity and burned the links and messed the old igniters up, I tend to believe it is the ECU.

Any opinions? ECU vs Injectors?

Thanks,
kerniew

 

You've done a pretty good job of troubleshooting your issue to isolate it to Rotor #2, fuel injection.

I can relate that this sounds like the dreaded 'running-on-one-rotor' problem, whereby the car loses all power and picks up a weird vibration. This is normally caused by a problem with the fuel injector pigtail and/or wiring harness that can be triggered with the car running by grabbing the harness just behind the waterpump and tugging on it - if the car goes into/out of 'failure mode', then you have an intermittent short in the harness to the fuel injectors. Due to their location under the UIM, they get very hot from engine heat and degrade over time.

Take $15.00 to your local Autozone and get 2x Borg-Warner Fuel Injector Pigtails - splice into the existing harness and you should be good to go.

The only other real cause is that you have a problem (usually a crack) in the distributor cap that's throwing off the timing, but that would be all the time, not just intermittent. Have a look at that and reply back.

(and Yes, I've been gone a long time on other hobbies, guys!)

 

Nice to hear from you LongDuck. Always appreciate you chiming in.

My attempts to mess with the wiring under the UIM didn't change the situation. Of course I was trying it from the back of the UIM. I'll do both of the injector pigtails and send the injectors for cleaning and flow testing. Then I'll chase after the ECU if that doesn't fix the problem.

I put on new rotor, distributor and spark plug wires. So that should be OK.

It'll probably be a few weeks, so stay tuned. I have some of my wife's hobbies clogging my schedule.

kerniew

 

This is an update on my GSL-SE.

As my debug session indicated, one of the rotors was not firing.

I pulled the injectors and sent them to Witch Hunter performance and they quickly found that one of the injectors was exhibiting an intermittant open. It would vary between 2 and 7 ohms when it was tapped. The injector was declared dead.

I immediately searched ebay and found a set from mrmazda7. I got the bid and had mrmazda7 send them directly to Witch Hunter. Gordon did the complete check, cleaning and parts replacement and promptly returned the injectors (1 bad, 3 good) to me.

I reinstalled the injectors and viola, my GSL-SE is back and running very well.

Thanks to the forum. Thanks to Gordon at Witch Hunter (highly recommend) and mrmazda7 (also easy to deal with).

 

Out of curiosity, what does Witch Hunter charge to do injectors?

 

$15 each, includes o-rings, bottom seal, nozzle plastic, a metal screen. (I don't have the technical terminology.) He did before and after flow testing, graded the pattern and included the documentation. He verified the bad injector and didn't charge anything for it. Gordon was very easy to deal with, particularly taking direct receipt of the injectors from ebay.