I have the 2.8 v6 in my 86 jeep cheroke, it's my winter ride.The heep has no mod other than a k&n filter and 2"exaugst. And my problem is when it get's really cold out the RPM's drop to a little slower than idl speed.But it won't die out, and giving it gas only gives me 200RPM's and it won't rev anymore. And it will start the same way every time it's only after i drive for a while that it does this. When I turn the jeep off and let it sit for a bit, and then restart it run's good for 15-20min's and then the same thing.I know most of you don't drive your car in winter, but any help on this would really help my out.

Thanks in advance.

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88 Camaro IROC-Z
350TPI
K&N filter , High flow exgaust (no cat's), automatic tran's shift kit

 

Haha, I've driven my car thru every winter since '94, and even thru a "state of emergency" NJ blizzard...

That's TBI, right? Have you done a major tuneup? I'd say to check also the coolant temp sensor, the timing, and to make sure the TBI is clean (using "throttle body cleaner for fuel injected engines).

How fast does the 2.8 get up to operating temp? (Do you have a temp gauge?) Sounds like something with the oxygen sensor... the computer starts to read the oxy sensor after the coolant temp's above 80 degrees Fahrenheit (or around that), the engine run time has been a few minutes, and the computer sees a changing value from the oxy sensor. (When the exhaust pipe is cold, the oxy sensor gives off one steady value; as the pipe heats up, the oxy sensor starts to work, and starts sending different values.)

Do you get a service engine soon light?


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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

The computer has a set itme (in sec.) before it reads from the O2 sensor. Jprevost can tell you about this completely. IT has two set variaboles that can be reprogrammed. On is for cold start and one is for when the car has not been steeing very long and is restarted.

In response to Mr Jeeps problem, hmmmm its puzzeling. Lets look at the obvious. after a 15 minute run it no longer wants to run. SO something is funky after the engine warms up. I have to agree that something in the tempuratur e reading must be wrong. Though even if you have a coolant guage in your dash, it is not what the computer reads. I would do a full major tune up as stated above, replace the O2 sensor(hey it cant hurt) and replace the coolant sensor that the computer reads from. ALso check form Vacume leaks with the old Carb cleaner around the vacume lines. Just keep it off the exhaust manifolds.

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89 Trans Am Turbo 3.8L All stock 43,000 miles #1053 of 1555

Past Thirdgen:
86 Trans Am w/ built 355TPI with SLP goodies and too much other stuff to List. One sweet *** car, wish I would have had a good enough Job to pay insurance on three cars so I could keep it, but for a 89 Turbo Trans Am w/ Low miles, I think I made the right choice!

 

thank's for the responce but this is and old school 2.8, no computer no fule injection.I guess i forgot the jeep is not in my sig.It's a v6 with a 2 barral carb.I going to tune it up tonight plugs,rotor,fule filter,and change the thromstat to a higher temp.

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88 Camaro IROC-Z
350TPI
K&N filter , High flow exgaust (no cat's), automatic tran's shift kit

 

thank's for the responce but this is and old school 2.8, no computer no fule injection.I guess i forgot the jeep is not in my sig.It's a v6 with a 2 barral carb.I going to tune it up tonight plugs,rotor,fule filter,and change the thromstat to a higher temp. the temp gage reads cold all the time I think that the carb is frezz over.

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88 Camaro IROC-Z
350TPI
K&N filter , High flow exgaust (no cat's), automatic tran's shift kit

 

I thought the Cherokee's in '86 were TBI injected... the thing that looks like a carburetor- no? And the carb isn't the E2SE (computer controlled varajet) either?


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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

It's not a TBI ,the closest thing to being computer controlled is the dash board clock.Do you think this might not be the original motor? When I put in a clutch last year the first one I put in was the wrong one.If it's not the original one how can I find out what it is?

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88 Camaro IROC-Z
350TPI
K&N filter , High flow exgaust (no cat's), automatic tran's shift kit

 

The 2.8 Jeeps WERE NOT injected. Jeeps didnt get FI untill '87. The problem sounds like the choke isn't working, it's staying shut. Check for power at the green wire for the choke, check the connection for corrosion, and make sure the linkage is moving freely. Those 2bbl vera-jet carbs SUCK! Could be time for a new one, or a rebuild. Go through ALL the vacuum lines too! They didn't use a very high grade rubber for those hoses back then, I'll bet you'll find most of them split on the ends.

I have an '86 2.8 Wagoneer, it had a hesitation when I first got it. I found that the barb had worked itself loose causing a major vacuum leak.
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Ya can't have too many fast Chevys!


[This message has been edited by CHVYPWR (edited October 27, 2001).]

 

The choke is a bit loose but it's closing when I start it.Should close again if the heep starts to run cold again?I think when it starts to act up it's not closing, or may be not all the way.I'm going to wait for the cold whether to see what it will do.

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88 Camaro IROC-Z
350TPI
K&N filter , High flow exgaust (no cat's), automatic tran's shift kit

 

Okay, cool, thanks for the info! (quoted too much)

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-Tom P (Hot rodded 1986 Firebird 2.8l)

[This message has been edited by TomP (edited November 01, 2001).]