1988 4.3 jimmy overheating and running rough


rigidhd
10-21-2004, 10:12 AM
My 88 4.3 jimmy has had an overheating issue at hi way speeds it seems to be fine at 40 -55 I have replaced the thermostat radiator is full and looks clean I have tuned it up new plugs rotor distributor cap, had the EGR valve replaced and had the leak in the throttle body repaired as well as clean oil and the transmission rebuilt. I take it to a local retail shop and they say it does not overheat there is nothing wrong they also are not driving it. I had it there yesterday has it was overheating losing power and doing a muffled backfire. I got it back after 300 bucks told it was all better it idles fine now and drives ok till it hits hi way speeds 65 - 70 then it begins to heat up to about 3/4 of the gauge. And then the power loss is back along with the backfire. Does anyone know what else it could be I know I need a 02 sensor but that should not cause these issues should it? I suggested to the shop maybe it was a blockage in the exhaust they were supposed to do a full spectrum analysis on it but only pointed out the EGR valve and the throttle body gasket and 02 sensor. Any help would be appreciated.

Rigidhd

BlazerLT
10-23-2004, 04:36 PM
Replace your rad cap.

Also, check timing for an overly advanced setting.

rigidhd
10-27-2004, 07:59 AM
Replaced the cap when I bought the truck in september. I took the truck to a local auto store and had the egr replaced and the throttle body gsket replaced the next day on the side of the road again with the exact same issue I had it towed back to the same shop and they kept it over night they said there was a plug wire laying on the manifold and the distributer was lose. They also told my wife who picked up the truck that the timming was a little off rather then fix te timming they turened the idle way up. also told her that we should run good gas through it. It still runs a little hot at highway speeds and like you I belive it is the timming and idle. I will have to pick up a new timming lite this weekend and idle the truck down. God my wife hates my jimmy I think it has the potential to be a great truck. Thanks for the insight.

Respect

HY-TECH
A.K.A Rigidhd
http://ironheadsportster.com

BlazerLT
10-27-2004, 06:47 PM
Take the truck to a another mechaic because that one is a complete scam.

Turning the idle up to compensate for bad timing, comon, you really take that load of bullshit from them?

Have a GOOD mechanic time the vehicle with the timing wire unhooked from the PCM under the glove box.

It is brown and beige wire that runs under the carpet.

Once the timing is set, reconnect the wire and clear the computer by removing the negative cable for 10 minutes and everything will be perfect.

I can almost guarantee your timing is waaay to advanced.

rigidhd
10-29-2004, 09:31 AM
unfortunatly, I did not pick the truck up from the shop my wife did. As I was showing my ass when I had to take it back last time. We have decided nothing goes to that magor auto repair chain again. Thank you for the advice I will have it taken care of soon.

Respect

Rigidhd

HY-TECH
http://ironheadsportster.com

BlazerLT
10-29-2004, 02:52 PM
I would get this fixed soon before you cause some damage.

coronaroma
11-24-2004, 01:33 AM
your radatior is cloged replace or flush your system

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