Need Advice - No Power & BAD MPG

awolo

New member
Whats up guys.

Im having some issues with my AllTrac and I need your help. I'm getting much more familiar with these amazing cars but, I need you veterans to lend some knowledge or maybe point something out that im not thinking of.

My car is my DD and I have not been driving it at all these past 3 weeks. Thank god for motorcycle's and good weather.

PROBLEM:
The car makes boost to 15psi - But she has NO pull/kick.
My mileage has been between 9-11 MPG!!!
As of late, she has been pushing coolant into the overflow bottle, enough to fill it up and have it drain out.


Here's the last months history. I'm going to be as accurate as possible so you guys have all the facts.

My stock exhaust was rusted out horribly, loud, and rattled. So it needed changed.

I replaced it with a full 3" cat-back. I also removed the stock cat and went with a 3" down pipe. Install was a PITA but she sounds great!
At this same time I installed, new NGK 6RE's and plug wires.

Upon my ehxaust install, I broke a exhaust manifold stud. So I had a leak which leaked all my boost, thus leaving me with no power and horrid mileage. I replaced the stud, she is nice and tight. Also made sure all of my down pipe bolts are staying tight, as they have been loosening themselves. :bangshead: See thread: viewtopic.php?f=50&t=44924

For maybe a drive or two, she was running GREAT. Pulled hard but still had bad MPG. But then went back to no power. I checked and re tightened loosened bolts.

I pulled the ECU fuse to let the car reset itself. Didn't help.

I do not have a constant CEL.

The car does not smoke, stutter, sputter, hiccup, anything. Turbo spools up fine as well. Small oil drip, but has been that way since purchase.

It is obvious that there is something wrong with the vehicle. No power + bad mileage would point to a exhaust leak or a boost leak. To the best of my knowledge, I no longer have any leaks.

Before I start throwing parts at her, which is never a good thing with problems. I have some questions for thought.
QUESTIONS:

1. Do you guys think that my O2 is bad? Possibly killed it when the stud bolt was broke and she ran super rich? Thus causing my bad MPG and no power?
2. Should I look into maybe using different plugs/wires?
3. It is possible that even though all the down pipe and exhaust manifold bolts are tight, I still have a big leak somewhere? (kinda leaning this way)


I know that throwing on some wider would hurt my MPGs and pull, but from 20-22 down to 9-11??

Any advice is GREATLY appreciated. I don't want to let this car go.
 

4rsnduction

New member
A good way to get solid answers is to have a smoke test performed on the engine.
Remove the brake booster vacuum line and introduce smoke to the engine and intake system via this port.
Use WOT so smoke can reach the air filter, but u dont want smoke and pressure to escape so plug the filter box hole with a rag.
If no smoke is detected this way then open the oil filler cap, drain all the coolant and introduce smoke via the radiator fill cap.
Smoke will fill your radiator and engine, if the head gasket is on its way out then smoke will invade the cylinders and escape out the exhaust/intake or smoke will escape via the oil filler hole.
This test will also find any exhaust leaks.

Any decent shop should have a smoke tester and if u tell them exactly how u want it tested there is less room for error.
85% of the time smoke tester will find your problem, at the very least if it finds nothing u now know its an electrical gremlin.
 

Kil'Jaden

New member
I'll start off with "I don't know", but I do know anytime I end up breaking a seal on my old mustang, its a good idea to replace it. My best guess is the problem is still around that previous leak, just maybe more subtle.
 

Mafix

New member
your knock sensor is pulling timing because you have a blown headgasket. you are getting water in the cylinder and causing detonation. so long story short....new hg time.
 

awolo

New member
Mafix":3jkjnv2i said:
your knock sensor is pulling timing because you have a blown headgasket. you are getting water in the cylinder and causing detonation. so long story short....new hg time.

I understand what your saying. But if it where the HG, wouldn't I have smoke out the exhaust?
I have never noticed/seen/had anyone tell me about smoke coming out of my exhaust.

I'm going to be looking into a smoke test ASAP.
 

Mafix

New member
not necessarily. head gaskets blow in many ways. the most common on these cars is a coolant passage to the combustion chamber. because these are forced induction they tend to blow more air into the coolant system then they get coolant in the combustion chamber.
 

awolo

New member
Mafix":2ubiz8ov said:
not necessarily. head gaskets blow in many ways. the most common on these cars is a coolant passage to the combustion chamber. because these are forced induction they tend to blow more air into the coolant system then they get coolant in the combustion chamber.

This is not what I wanted to hear. But thank you for your input. It is greatly appreciated.

I'm going to look into a smoke test. That will tell me which way to go.
 

awolo

New member
4rsnduction":6fw99dee said:
A good way to get solid answers is to have a smoke test performed on the engine.
Remove the brake booster vacuum line and introduce smoke to the engine and intake system via this port.
Use WOT so smoke can reach the air filter, but u dont want smoke and pressure to escape so plug the filter box hole with a rag.
If no smoke is detected this way then open the oil filler cap, drain all the coolant and introduce smoke via the radiator fill cap.
Smoke will fill your radiator and engine, if the head gasket is on its way out then smoke will invade the cylinders and escape out the exhaust/intake or smoke will escape via the oil filler hole.
This test will also find any exhaust leaks.

Any decent shop should have a smoke tester and if u tell them exactly how u want it tested there is less room for error.
85% of the time smoke tester will find your problem, at the very least if it finds nothing u now know its an electrical gremlin.

I KNOW this is a stupid question, but this all gets done with the car not running correct?
 

awolo

New member
Thought so. :oops:

Anyway, im borrowing a smoker today/tomorrow and im going to give this a shot. Ill be sure to report back ASAP.


Im curious though. The car ran top notch before the exhaust install / broken manifold stud / etc. Does anyone have an idea as to what "may have" caused the motor to blow the HG?
 

awolo

New member
88gt4DE":20g8wb44 said:
DId you have to drill out the broken stud ?

No, used a bolt extractor. Removed it. Replaced with new stud and made sure she was tight.

NOTE: I never removed the exhaust manifold during this process.


Why do you ask?
 

awolo

New member
I see. So your saying the full 3 inch exhaust allowed enough of a power increase to allow the HG to let go?

I'm assuming this is because the stock HG had 158,xxx miles, and that a new HG would not do the same thing. Or am I assuming wrong. It would be a shame to do the HG, bolt her all back up and pop it again, that's all i'm getting at really.
 

jaydog82

New member
15psi might hag been to much for it, did you reset the mbc after the exhaust? Do you have an aftermarket boost gauge? Maybe the boost increased after the exhaust.
 
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