'89 SHO random hesitation

[stlooiesho]

It happens after the car is warmed up, but it is random & it happens under a various conditions such as acceleration or steady-state cruising. Sometimes it occurs once or multiple times, sometimes mild or so severe that I have to push in the clutch. It may or may not still happen after I re-engage, so i'll try to downshift and/or coast & try again. There are no codes. When it happened having oil & fuel pressure gauges hooked up, there was no significant variation before, during or after. Seems to happen more often when it is warmer out, like between 70 & 80 deg. This morning, it was about 55 deg, and it did not happen at all going to work, a drive that lasted close to an hour. Could it be a MAF sensor? Would a bad MAF throw a code?

Question 2, I have an Autometer A/F gauge, I have a t-tap connector on the front O2 sensor, but it is only displaying a full rich light. When I tried tapping the other wire, there was no light at all. Of the 3 O2 sensor wires, two are white, one black. Which white one should I be hooked up to?

 

[Bob Gervais]

When it happens, is it a misfire, or does the car just lose power?

I'm leaning towards a fuel problem if it's just losing power. Filter? Pump maybe?

Not sure how far away you guys are, but I'm sure James from St. Louis SHO can get you up and running like brand new in no time.

http://www.stlsho.com/

[email protected]

 

[stlooiesho]

It's running about 32-34 psi of fuel pressure. The hesitation jerks the car, sometimes violently, especially if it happens multiple times and that's when I push in the clutch in order to stop it. Tach does not jump when it occurs. But it is not simply just losing power. It can be a slight hesitation or it can **** the car, I guess it would be more of a misfire. It's getting close to where I need to do another front-end 60K, but don't know if these are any symptoms of that, right?

 

[Bob Gervais]

Cam sesnor or crank sensor will do that, although either one of those issues should set a CEL. I didn't see mentioned in your original post about having a CEL set. Have you run the codes? That would be my first step.

 

[elarm1]

Clean the MAF and see if it clears up

 

[St Louis SHO]

Pull the rear spark plug wires. My bet is that they are full of water....

 

[stlooiesho]

Okay, will look to see if there is water in the rear spark plug wells tonight. Would it be bad spark plug seals causing water to get in there? And in response to an earlier post, I did run codes & there are no codes (I stated it in the middle of the original post ... probably easy to miss), though that is the right place to start. Thx for the replies...I'll keep everyone posted.

 

[SHOspazz92]

Okay, will look to see if there is water in the rear spark plug wells tonight. Would it be bad spark plug seals causing water to get in there? And in response to an earlier post, I did run codes & there are no codes (I stated it in the middle of the original post ... probably easy to miss), though that is the right place to start. Thx for the replies...I'll keep everyone posted.

Somtimes the Actual spark plug Wires to not seal well against the Valve Cover, Allowing water to get in them. I've had this issue a few times with my car. It'***** or Miss.

-Sam

 

[St Louis SHO]

Got my race car out yesterday and had this issue So, it was fresh in my mind...

 

[stlooiesho]

Any ideas on hooking up the Autometer A/F gauge?

 

[SHOspazz92]

No Idea. Does it have instructions?

 

[Mrhappytuzi]

How corroded is your DIS? I had this issue after i had a carwash once. It hesitated,bucked and it would not even let me put a bit of throttle on it or the engine would just try to **** it self. I barley made it home. I had checked the plugs and there were no water in them. Pulled the DIS off and noticed there was a TON of corrosion on the intake and on the back of the DIS. I cleaned up all of that and i had no problems with hesitation and bucking after that. Another thing you could try to do is swap out the dis module with another one since there could be a possiblity that its on its way out.

 

[frosho]

How corroded is your DIS? I had this issue after i had a carwash once. It hesitated,bucked and it would not even let me put a bit of throttle on it or the engine would just try to **** it self. I barley made it home. I had checked the plugs and there were no water in them. Pulled the DIS off and noticed there was a TON of corrosion on the intake and on the back of the DIS. I cleaned up all of that and i had no problems with hesitation and bucking after that. Another thing you could try to do is swap out the dis module with another one since there could be a possiblity that its on its way out.

That was heat sink compound that you cleaned off, not corrosion. It belongs there. You problem was likely a loose DIS bolt causing a bad ground.

 

[Mrhappytuzi]

I forgot to mention that i did put thermal compound back on but.. it was actually just corrosion.

 

[stlooiesho]

No oil or water in either the front or rear plug wells. I don't know if the cooler weather that we've had yesterday & today is making a difference, but the hesitation issue has not manifested itself since then.

 

[Inkertinker]

While doing a front 60k on stlooiessho's car James found this.

 

[Bob Gervais]

Yeah, a water pump lodged in a spark plug well will do it every time.

 

[kikkinasphalt]

Yeah, a water pump lodged in a spark plug well will do it every time.

i like you. you make me laugh...... waitress .. get this man a beer.

 

[Bob Gervais]

i like you. you make me laugh...... waitress .. get this man a beer.

Five feet from the fridge, 6 beers deep already. It's gonna be a good night.

 

[Inkertinker]

i like you. you make me laugh...... Heather .. get this man a beer.

lol... Fixed.