This is a repost from the Tech forum. I'm trying to diagnose a "hesitation" problem that my car has at all rpm levels, both on and off throttle. I've traced the first occurrence of this problem to a 2-day window that my tuner had my car at his shop. He was lowering my vtec point with my Unichip ems. I set out tonight to undo the new vtec wiring that my tuner installed to try and isolate the problem.
While digging around the ecu tonight, I found that the "c" plug in my ecu wasn't snapped in. It was pushed in most of the way, but definitely not "snapped" in. I snapped it in, started the car, but I'm still getting that "hesitation" problem.

Next, I look at the tps. My tps has given me trouble for 2 years. When the engine is running, if I touch any of the wires at the plug, the engine will stumble. The connection at the tps is very precarious. A few months ago, I replaced the plug. That didn't solve the bad connection problem. More recently, I replaced the tps itself. That didn't solve the bad connection problem. The engine still stumbles if I touch the plug, and I can only imagine that this poor connection has something to do with why my car is running so rough.

Am I the only one that's run into this problem (bad plug + bad tps = bad connection)? Short of soldering the wires from the plug to the tps itself, I'm running out of ideas.


Modified by Batoutahell at 12:52 AM 4/24/2003
Edited again to remove the "-" from the word "vtec" so I don't get bagged on any more for my faux paux. Using the word "v-tec" is almost as bad as lifting in the middle of a high speed kink.


Modified by Batoutahell at 7:56 AM 4/25/2003

 

Anybody?

 

Jim - what is "v-tec"? j/k.

Does your engine hesitate even when it's idling, or just when you're giving gas?

Also, it might sound trivial, but have you checked your distributor to see if all parts are in good working condition? Is it misfiring due to bad rotor, cap?

Oh yeah, lastly, there is a vacuum hose on the intake manifold (?) that also can cause hesitation. I forgot the exact location of this hose, but IM kengs, he had the problem before.

Just throwing out some other ideas that might cause engine hesitation.

 

I had the same problem, my solution was this:

I took off the TPS plug and took a small piece of metal, then pried the prongs on the sensor its self up a little. It made better contact than before and its been a year since anything has happened.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EVIL CETANE &raquo;</TD></TR><TR><TD CLASS="quote">I had the same problem, my solution was this:

I took off the TPS plug and took a small piece of metal, then pried the prongs on the sensor its self up a little. It made better contact than before and its been a year since anything has happened. </TD></TR></TABLE>

hehehe - the first tiime this happened, we were driving back in the snow from Omaha (dyno tuning) to KC & I offered to stick my chewing gum on the plug to hold it steady Jimmy didn't go for that

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Cosworth &raquo;</TD></TR><TR><TD CLASS="quote">Jim - what is "v-tec"? j/k.

Oops, I deserved that.

Does your engine hesitate even when it's idling, or just when you're giving gas?

It hesitates on and off throttle. When I first start the engine, it happens mostly only at high rpm (about 7K). The more I drive the car, it starts stumbling at all rpms, even as low as idle. However, after the car sits for a while, and especially after I poke around the tps, it will start up/idle just fine. It will start to stumble again when I rev it up, and the whole "getting worse" process starts again.

Also, it might sound trivial, but have you checked your distributor to see if all parts are in good working condition? Is it misfiring due to bad rotor, cap?

Yep, I checked the cap/rotor/wires, which are all newish.

Oh yeah, lastly, there is a vacuum hose on the intake manifold (?) that also can cause hesitation. I forgot the exact location of this hose, but IM kengs, he had the problem before.

I'll IM kengs. With the jrsc, I'm usually pretty sensitive to vacuum leaks, but maybe I'm missing one.

Just throwing out some other ideas that might cause engine hesitation. </TD></TR></TABLE>

Thanks for the suggestions, Sean. This is a frustrating problem, so keep 'em coming.

 

Did you get that memo? Ah.. yeah, it's just we're putting new coversheets on all the TPS reports before they go out... That would be grrrreeeeaaaat.

Couldn't resist, sorry

 

EVIL - the more I poke around the sensor/plug doing the various Helms voltage and resistances tests, I "kind of" think it's a bad ground wire. My diagnosis harkens back to the time a year ago that Budman is referring to when (correct me if I'm wrong Jeff), we also ran all the tests and concluded it was a bad ground wire. When the engine is running, I can shake the tps wires at the plug and make the engine stumble and stall. If I shake just 1 of the 3 wires at a time (difficult not to disturb the other 2 wires at the same time), it seems that the gr/blk ground wire is the sensitive one.

However, as to the ground wire, I've checked continuity from the tps plug to the battery, and continuity seems ok. I've had 2 tps' on the car, so I'd like to think the problem isn't the contact prongs in the plug, but I'll remove it and give your idea a try tonight.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by io_burn &raquo;</TD></TR><TR><TD CLASS="quote">Did you get that memo? Ah.. yeah, it's just we're putting new coversheets on all the TPS reports before they go out... That would be grrrreeeeaaaat.

Couldn't resist, sorry </TD></TR></TABLE>

haha, i was thinking the same thing!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Batoutahell &raquo;</TD></TR><TR><TD CLASS="quote">Modified by Batoutahell at 12:52 AM 4/24/2003
Edited again to remove the "-" from the word "vtec" so I don't get bagged on any more for my faux paux. Using the word "v-tec" is almost as bad as lifting in the middle of a high speed kink.


Modified by Batoutahell at 7:56 AM 4/25/2003</TD></TR></TABLE>

LOL Sean got OWNED

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dawhiteboy &raquo;</TD></TR><TR><TD CLASS="quote">

LOL Sean got OWNED </TD></TR></TABLE>

What fun is it without killer oversteer into a guard rail?