1987 Chevy Camaro 2.8L V6 70-80,000 miles.

Brand new distributor car runs nice but randomly surges. I had a code 42 so I took my old distributor out replaced the ignition module and pick up coil but it was randomly surging and surging when I would press the gas pedal. So I then decided to buy a new distributor and drop it in. Code 42 disappeared with the new ignition module. I timed the car to 11 degrees with the new distributor (tried for 10 but it kept going to 11) the car was originally on 8 degrees. The TPS was on .50 so I changed it to .54/.55

I've never had this surging problem untill removing the distributor so something is up...I've installed distributors in my pontiac all day so I know what I am doing. Timed with a timing light and everything. Just can't seem to figure this surging problem. No trouble codes, and no stalling just random surges. Should I bring it back to 8 degrees? who knows how long it's been on 8 degrees.

 

The factory timing on the 2.8's is 10* BTDC. It should be set there. If you are having the dizzy move on you then have a friend shut off the car while you hold it in place then tighten down the hold-down bolt. The TPS voltage is slightly high. It should be between .49 and .53. I had a surging problem until i set the TPS down to .49 volts. Also are you sure that you dont have any vacuum leaks? A vac leak can cause many days of head scratching. Also how new is your TPS? They can develop bad spots in the resistance coil. Now that you have removed the ignition problems, the others that were lying under the surface are showing their ugly heads. The fact that you had a bad distributor is why the timing was set at 8 degrees instead of 10 where it should be.

 

thanks for posting, the only lines I could have possibly hit is the line above the dizzy going into the black cluster of wires near the firewall and the back T connection line. I checked both and both looked fine. It doesn't throw any codes and runs very nice the idle just surges down very low for a second randomly (could be 2 minutes or 6 minutes apart usually when driving) This did start occuring after adjusting the TPS to .54 maybe I will bring it back to .49/.50. I thought .54-.56 was stock per GM manual? anyway my TPS is the OEM and I have a new one to test. This all started with water leaking under my hood ruining my Dizzy. I replaced the Dizzy but havent replaced the wires its was about 8 months ago. New ignition coil. Think it could be a arced wire due to rain? or possibly me adjusting the TPS ruined it...lol...

Also the dizzy in it was good just a bad ignition module, I just decided to replace the dizzy because water had made it's way in and ruined the module along with god knows what else. Timing was set at 8* per an automotive shop for about 2 years. After installing new dizzy I set it at 10-11* closest to 10 I could get since it's a pain trying for dead 10.

 

Adjusting the TPS would have no bearing on your dizzy. Each car is different with the TPS voltage settings. Mine likes it around .49-.50. Some like it higher even up to .64. Sometimes those vac lines look ok but have a crack in them causing a leak. I usually just take a propane torch and turn on the gas BUT DONT LIGHT IT! Then i run it along each vac line until the engine either speeds up or stumbles and then i have found my culprit. You mentioned water leaking into your old dizzy. Did you check the plug ends for corrosion? Im talking about the ones that go into the ignition module. Also touch all the rubber lines. If black rubs off on your fingers, they are bad and should be replaced.

 

I didn't read everything here but, did you unplug the little grey connector by the ac stuff when you set the timing?

 

He stated that he knew how to install the dizzy and set the timing so i didnt bother mentioning that lol

 

Yes, I unplugged the EST connector the 1 wire tan/black connector by the firewall. Engine was warm and set the timing to about 10*-11*

The ignitions control module connections seem very good and clean.

I originally had a code 42 which was a bad module due to rain getting in the dizzy. Timing was originally at 8* and I replaced the dizzy with a new one and timed it to 10*, I then adjusted the TPS from .49 to .54/.55

Code 42 is no longer a problem, car runs very good except for the stumble and it last litterally 1 second and sometimes it stumble lightly and something with a little more force at random times.

It has something to do with timing, or the tps. This occured after tampering with either one of these two. Tomm I will set TPS to original specs of .49 and Timing back to 8* and let you guys know.

 

Dont do them both at the same time or you will never know which one was the problem. Set the TPS since its easier to do then if your problem remains, then you know the timing is probably at fault.

 

I'll post an update after class when I am able to work on the car. I planned on doing exactly as you state 1 at a time. This camaro has 100,000 less miles than my pontiac and it's such a pain in the ***.

 

I know this isn't a tech post but, that is exactly why miles on a car mean nothing at all. I've seen 200k+ cars running better than cars with less than 30k and always getting maintenance. Every car, person and scenario is different. Hope you figure this out.

 

2 problems in one sanario. Originally had code 42 which ended up being the ignition module, replaced the whole distributor and got rid of the code 42. At the same time I had a random surge problem which ended up being a bad maf sensor. I was just doing random checks and stumbled upon the "tap" test. Sure enough it surged everytime I tapped the MAF sensor. Bought a new maf sensor problem solved But now my idle is alot lower than it use to be and I realized my TPS has a broken upper bolt. Do you think it's neccessary to drill and tap that bolt out or will the bottom bolt hold good? it's at .54 and I couldn't move it.

 

If you drill that out, you HAVE to drill straight or its toast. Your best bet is to get another throttle body out of a junkyard.They should be cheap enough. Unless you have access to a drill press or can make a jig that hold the TB straight while you CAREFULLY hand drill the broken screw out. At the same time, watch your depth. Going too deep is just as bad as drilling crooked. Its hard to say if only the bottom bolt will hold it. It can possibly move. If its not having any issues with the volts at .54, id leave it alone, unless that TPS is bad. What are your idle RPMs? If its around 700-800, that should be fine.

 

I would open the throttle blade by hand and watch the tps to make sure its not trying to push out or anything. If it doesn't, you should be fine.

 

since u replaced the distributor and adjusted the tps i would of assume u did an idle relarn after doing such work. if not then that is why it is serging. get the engine warm then set the timing. disconnect est. set timing then reconnect est. clear codes. (disconnect battery 30sec - 1 min) then connect battery. then do an idle relarn after reconnecting the battery. any time u disconnect the battery u have to do an idle relearn or the car will run wierd.