SOS

Who did the rebuild? You can't bring it back to the shop that did the work?

Strosek

I'm starting to think a shouldn't have mentioned the rebuild.... its
not the rebuild. The car did the SAME thing before the rebuild. I only mentioned the rebuild to eliminate mechanical parts as suspect.

This is a pre-existing problem since before the rebuild. 110%

Exhaust is all new as is the cat.

Thanks

techman1

1 thing that comes to mind - the throttle switch. I recall you checked to ensure the throttle was opening all the way. If I recall the switch sends a signal to the DME when it is fully opened. I believe this will affect the timing/fuel. Others more familiar may chime in...

Strosek

I'm starting to think a shouldn't have mentioned the rebuild.... its
not the rebuild. The car did the SAME thing before the rebuild. I only mentioned the rebuild to eliminate mechanical parts as suspect.

This is a pre-existing problem since before the rebuild. 110%

Exhaust is all new as is the cat.

Thanks

bcameron59

fuel pressure?
mass airflow sensor?
getting OBD info definitely will help confirm or eliminate many suspects, pure speculation right now

Quadcammer

well it seems you've exhausted the basics.

You will likely need to look at a/f and timing, fuel trims, etc.

trophy

One area where timing is taken out of the system is via the Knock Sensors. If these are faulty or the circuit within the ecu is faulty the ignition will be retarded 9 degrees, this is easily enough to make the car feel like it has no power.

The other items also used by the ecu to manage timing and fuel as Quad has illuded to are the Head temperature and Intake temp sensors. If these are faulty it can essentially put the ecu into limp mode (retard timing), again making it feel like there is no power.

All of the above can be tested with either Bosch Hammer or the procedures in the workshop manual.
Start with the sensors. make sure they are giving the right resistance (ie, sending the correct signals to the ecu) If these test ok the issue is most likely an ecu issue.

Mike J

Perhaps a little more data on how it runs. Does it lack power right from idle? High RPMS only? Just full throttle? Is it bogging or just not pulling? Any feel of misfires? Smooth or rough?

If you also have the same car, would you be open to swapping the distributors? That would eliminate any mechanical advance problems, etc. The timing for the distributor is correct, right? (you confirmed that its TDC compression for #1 - not a notch out..).

Cheers,

Mike

Strosek

Not sure how to reply with quotes so I'll do my best...

bcameron59:

Fuel pressure wasn't tested by myself but was tested by a class a mechanic that I know and was told that it was "fine".
Mass Air Flow sensor was delaminated so we replaced it being that it was damaged and was a possible likely cause of our problem so its been replaced and is brand new.
DME reading: We have a Hammer but no connector for the obd port.. ordered one and once that arrives I'll test and report back.

trophy:
Knock sensors are an area that I haven't tested... Now what would be the test for a knock sensor... Is it something I can do with a simple meter or should I wait for the Hammer connector to arrive.

Head temp sensor was my first guess so I tested it myself and it was perfect as per manual and resistance went up and down as it should with temperature change. Its fine!

Intake air temp sensor: Is it not part of the MAF sensor on that year? Not 100% sure but I think it is. If it's not I'll test it...if it is it would be fine as the Air Flow meter is new.

Mike J

Car starts first crank and idles like it has no problems... Smooth
Engine does not hesitate or fumble backfire or do anything strange other then be REALLY gutless and like I said earlier I have a 3.8 built like this and it's the bomb so I know what it should be... feels like 100HP tops!!

Thanks to everyone for the feedback it's not an easy fix and my friend spent a ton of money on the rebuild and really can't enjoy the car so I'm trying my best to lend a hand

trophy

What year is the car? the '95's have a separate Air temp sensor that is in the rubber hose that is between the throttle body and the MAF. (not sure of the 96-98's)

The only way to test the knock sensors is with the Hammer, fault codes 1_31 and 1_32 indicate either of the knock sensors are faulty. If they are faulty the engine is retarded 6 degrees until they are fixed.

Fault code 1_33 is a problem with the knock control circuit in the ECU, this then requires replacement of the ECU (there maybe someone that can repair but I don't know of anyone). This also has the ignition retarded by 6 degrees.

The only way of testing the knock sensors without the hammer would be to disconnect the sensors and then drive the car, if this makes no difference to how the car feels then they are faulty. With them disconnected the ignition would be retarded by 6 degrees and the car will feel very sluggish. DISCLAIMER: doing this would be at your friends own risk, yadda yadda..

Strosek

The car is a 96 and does have a seperate intake air sensor which I'll test.... and as soon as the hammer cable arrives I'll do further testing of the knock sensors.
Thanks very much for the detailed reply it's very helpful.

trophy

Keep us updated on what you find.

Vorsicht

Another thing to check which relates to timing is the flywheel reference sensor. It tells the ecu the engine's rpm.

Strosek

Sounds good!

Cable for hammer should be here soon and I'll report back with findings.
Thanks guys!

trophy

I just noticed that you said that the car had the Black plastic Manifolds, but the car was a '96. Something seems a little off. All the '96 cars were varioram and came with the new OBDII 88pin ecu's (Except in Europe)

The '95's with the plastic intake used OBDI and the Bosch 55pin ECU.

Was the engine's intake backdated when the engine was rebuilt?

Also, unfortunately the 964 ECU won't work with the 993. the 964 uses a 55 pin Bosch ECU, however there are some major differences in the Ignition side (Ignightors etc)