Chugging/Hesitation

[Guest wayne2reattas]

Hello everyone,

I put this post up quite awhile ago! I have just this past week tried to find the original problem. The car chugs/hesitates until I am over 35 mph. Yesterday I did the following:

1.) Switched MAF with a known good one

2.) Checked fuel pressure ( it was fine)

3.) Replaced the TPS with a new one adjusted to .40

4.) Replaced the PCV

5.) Checked all wires for spark

6.) Pulled and checked all plugs

7.) Cleaned IAC (which had been recently put in) made sure it was adjusted correctly.

Still have the same issues. On acceleration it chugs/hesitates until I am over 35???

Need some help what to do next?

Thanks!!!

[Ronnie]

I would try spark plugs and wires. Have you checked the ignition pack for gray matter oozing out of it? If you see any change to the Delco ignition setup.

[Guest wayne2reattas]

There is nothing oozing from the coil pack. I replaced the plugs and wires about 10,000 miles ago. I just read a post with someone having same type of issues. It was also recommended to replace coil pack. I put mine on about the same time I replaced plugs & wires. I am going to switch coil packs with my other Reatta on Wednesday and see if that makes a difference. Thanks for the response!

[D-a-n-i-e-l]

replace your 02 sensor. It does not always sen a signal as being bad. I recently had a simular issue and went through many other checks and replacements, before replaceing the 02. (I honestly believe a high consontrate of seafoam in the fuel caused my issue. (one can in like 3 gallons, just wanted to really clean the fuel system)

[Guest wayne2reattas]

Thanks Daniel..... Will try that also.....

[Guest wayne2reattas]

The car seems to run fine when its cold. But once the temp gets over 104 the problem seems to start.

[D-a-n-i-e-l]

I would go all-in on the 02. The ECM changes from open to close loop right around that temp.

[handmedownreatta]

a new o2 senser increased my highway mileage from 22 to 28.

[padgett]

Think a malfunctioning O2 would show up in the BLM and instantaneous. Have to record while driving. If it stops transitioning it will set an error. Certainly a possibility.

[D-a-n-i-e-l]

I had one that seemed to be sending the correct signal and the computer never through a cold. Heck even watching it while in diagnostic mode it was showing the correct readings. So they can go bad and not throw a code, granted it is nott too common from what I have seen. I had tried everything else and the 02 was around a month old.

[padgett]

And BLM didn't go wonkey ?

[D-a-n-i-e-l]

Nothing from the BCM. I had replaced: all coils, ICM, CPS, IAC, plug wires, TPS, and spark plugs. All had no effect on the issue, and refused to believe that my new O2 could be bad. So I spent alot of time checking everthing else.

[Guest wayne2reattas]

Daniel , What O2 sensor did you replace?

[D-a-n-i-e-l]

There is only one on a Reatta. If you are seeing two listed it is because one has the factory adapter and the other is a universal with no connector installed.

[Guest wayne2reattas]

Thanks.... Going to give it a try Tuesday night. On the way home from work tonight it was really bad when I would accelerate between 55 and 60. Hope this is the problem! Running out of patience and money!!

[padgett]

Hope it works, what you are describing is a classic secondary ignition problem and the speed (above 45 mph) points to the coils.

See particularly step 3 (coil check) in the diagnostic chart C-4f-2 on page 6E3-C4-15 of the 89 FSM. All three coils should be close between 10k-13k ohms.

Cost is zero other than some time. If you still have might also check the coilpack you replaced.

BTW this will usually show up first in a low rpm/moderate load/lean (closed loop) condition. When cold you are running open loop and the mixture is richer.

[Guest wayne2reattas]

Car is finally fixed--- not sure now what the problem was... I pulled off a plug wire to put the O2 sensor in. After I put the sensor in I saw that the boot came off the plug wire. then I noticed the plug wire was burnt. So I fixed the plug wire and put it back on. The car runs GREAT again. Now I am wondering -- was it the O2 sensor or the plug wire?

Also as Padgett advised I checked the ohms at the coil. They are reading 14k to 14.3k. I think the coil pack is still under warranty. Do you think I should take it back? I want to thank EVERYONE for all the responses.

[padgett]

Might just be the calibration on your meter, is not far out, most common is either low (shorted coils) or an open, would not worry about 7.5% high. OTOH I do not care for the Magnavoxes but then I have a ready supply of Delcos so I'd take it back and put the money toward a Delco.

ps by "BLM" I meant Block Learn Mode. The ECM tunes itself as you drive, first with the "Fuel Integrator" (ED19) for short term changes, and if the change stays for a long time, the BLM ((ED20) changes. Both begin at 128 and will calibrate rich (higher) or lean (lower) in 500 rpm "blocks" for a particular "Load Value" (LV8) which is a mixture of TPS, MAF, MAT, and a few other things. You have to read at your common cruising speed on a level road so you are seeing the right block.

If the O2 sensor drifts, it will show up in these two correction values. My experience is a tad rich (132-134) does not mean much but then I never like to run too lean: power and mpg are liable to increase slightly right up to when a piston burns a hole.

GNs at the drags will often pull the battery to clear out the tables and make their runs at a flat 128/128. Some say it helps.

[Richard S]

I'm going with the plug wire. However, if one wire was bad, why not spring for a set of wires? They are very inexpensive, and most of the aftermarket stuff is better than OEM. When's the last time the plugs were changed?