3.2 experts - please give me your 2 cents

mjshira · 09-13-2003, 12:50 PM

In the past I have posted this problem here and thus far I have done all the things you kind folks have recommended. However, the problem is still happening. So here goes:

Conditions:

1) the car must be at normal op. temp (usually driven for 30 minutes+)

2) after that point the car can be driven with out a problem until the problem happens. This could be 5 minutes or 2 hours. (however it has gotten much more like 5 minutes)

The problem:

The car suddenly loses power. If you give her some gas she'll try to come back but only with some limited success. Then the problem will go away for a few seconds/minutes before coming back. The longer you drive the car the worse it gets.

What I have done:

1) DME relay - changed recently

2) Cyl. Head Temp - change recently

3) AFM - changed today! ;-)

4) timing and crank sensors - changed

At this point I am really at a loss. Anything that anyone change recommend would really help. As you guys can see I've got some $$ in the problem and I want to see it fixed so that I at least feel like I won, you know what I mean?

Thanks ahead,
James

mjshira · 09-13-2003, 12:52 PM

actually it is more dramatic than I wrote above - the car acts like a bucking bull when this condition happens!

Milu · 09-13-2003, 12:59 PM

Two more possibilities come to mind:

some kind of contaminant such as a lot of water in your petrol

a minor electrical glitch. have you checked out: rotor arm and distributor cap, plug leads, connections?

I would also check the cyl head temp sensor again. Good luck

masraum · 09-13-2003, 01:12 PM

Have you changed the fuel filter, also, possibly check the inside of the gas tank for contamination.

mjshira · 09-13-2003, 01:12 PM

thanks Milu. The car has had a complete tune-up. I'll re-check the cyl. head temp sensor.

mjshira · 09-13-2003, 01:16 PM

fuel and fuel filter have been changed. this has been happening for the last year (I only drive the car about 3K a year at the most). It is only of late that it has gotten worse.

silverc4s · silverc4s's Garage

Have you removed, cleaned and replaced the ground strap from the trans to the chassis?
Might also check for good grounding of DME box/ good clean contacts in all the DME connectors...;-)

Jim Smolka · 09-13-2003, 05:18 PM

Also, hot wire the fuel pump. This is done by jumpering a red wire in the fuse box to the fuel pump fuse. If this 'fixes' the problem, then look for a 12VDC proplem supplying the fuel pump (DME relay etc).

If the above does not work, then swap out the fuel pump with a know good one.

From there, either clean and adj or replace the speed sensor on the flywheel. The reference sensor should be good, since the car starts well.

mjshira · 09-13-2003, 05:20 PM

thanks Jim, what about the coil? Since I have changed everything but the coil, the DME itself and the fuel pump, what do you think?

jtratza · 09-13-2003, 06:13 PM

How bout the throttle valve switch? I had a similar experience some years ago and if I recall I believe that was the cause. They're not expensive and easy to swap with someone.

afterburn 549 · 09-13-2003, 06:17 PM

i vote coil

mjshira · 09-13-2003, 06:21 PM

i just checked Waynes book again. It says that when your fuel pump is loud that maybe a sign that it is ready to be changed. The problem could be the fuel pump going in an out... thanks to everyone for your posts, this is sure adding up to be an expensive process

catuck · catuck's Garage

Check for a vacuum leak. Mine ran like that when I had a vacuum line hooked up wrong.

Jim Smolka · 09-14-2003, 08:25 AM

Chris,

You have a good point, check for vac leaks esp where the small hoses are that connect to the 2 fuel pressure regulators, and there another small vac hose in the center back. Sometimes the intake manifold bolts are not tight.

mjshira · 09-14-2003, 08:50 AM

these are all good points. However I want to add emphasis to the point that this problem

a) only happens when the car has been running for a period of time after it gets to normal op. temp

b) it is sporatic - here one second, gone the next.

makaio · 09-14-2003, 05:34 PM

Does your car have a cat converter on it? I had a ford ranger years ago that had a similar problem because of a bad cat, that was plugged up. It would buck and snort, along with losing power.

mjshira · 09-14-2003, 05:36 PM

thanks Matt. I do, would yours do this sometimes and then run normally others?

kepperly · kepperly's Garage

I vote for plug wires, I took off one morning in my 87 carrera and didn't make it a block when it shut down. replace one bad plug wire . 10kmiles since no problem.

keith

Tim Polzin · 09-14-2003, 07:33 PM

Kind of a far fetched possibility, but I had a similar problem on my 86. Car would run fine, then lurch a bit, then run fine again. Turned out to be a broken wire on the engine harness side of one of the plugs for the flywheel senders.

Also, have you looked at your distributor rotor?

Tim

JR Indy · 09-14-2003, 07:39 PM

Tough to figure out without more data. Do you have access to any electrical test equipment? A scope trace of fuel and spark when it occurrs would be helpful.

But, to throw another known problem out there, the DMEs have been known to have solder crack problems due to flexing of the circuit board. Sounds like you've replaced about everything else.