1997 Cherokee Issues

[PDXGraham]

it was the pick-up coil that i replaced.

 

[PDXGraham]

here is the current SITREP

it turns over just fine but wont start unless the throttle is at least half open. when it does idle its sounds and feels likes it has crossed wire or missing cylinders and the tach jumps around like its on meth. smokes like a sonofabitch. did new plugs, the wires are all in the corrects order. check fuel presure and the relay, they are both good. replaced the pick-up coil, if the CPS is bad will is still turn over and idle? i heard that when they crap out it wont even crank over. thats the next box on my checklist

 

[Tim_MN]

Did you inspect and clean all the wires and connections ? Did you load test the battery ?

There is no magic in a 97. You need to have a solid foundation for anything to run correctly. Fuel, air, spark, all delivered in the correct proportions, and at the correct times. The only way to be sure is to test. Most tests are simple.

 

[ElDiaOctavo]

Is the firing order correct?

 

[FlexdXJ]

I've had my 97 since Jan 02, and despite all that I've read about the changeover year being a basket case, it's actually been far more reliable than any other vehicle I've ever owned or driven.

Is the CEL on? Have you scanned it for codes?

I agree both my 97's have been very reliable. Sounds like a grounding issue to me.....

 

[PDXGraham]

havent been able to do much tinkering this week before or after work but when friday comes up ill be elbow deep in that bitch. after i get it running i HAVE to pull the engine cause that rear main seal flows like the willamatte river

 

[PDXGraham]

well friday is here, gonna triple check all the conections, clean any bad wires and snug up all the connections, i also got a new CPS so cross your fingers i get her running

 

[PDXGraham]

SITREP

CPS didnt help, we checked and fixed a lot of messed up stuff. here is the weird thing, when we hook up a hose to the port on the fuel rail (for checking preasure) and let the fuel drain into a can the jeep will start and idle. it still runs like piss but it wont even start without that hose "purging the extra fuel". also when it does idle it is dumping TONS of fuel into the engine and out the exhaust. is it possible its flooding itself and refuses to run? what is the cause of something like this? MAP sensor?

 

[xj upnovr]

I let a 1992 sit for about 6 months over this past spring, and didn't put in any ethanol-stabilizing additive. My initial operating condition was exactly as the OP describes. I drove it and the injectors rid themselves of what was eating them. Fresh gas and some injector cleaner made the problem history.

Don't underestimate the lousy quality of fuel available today. Hopefully that's all it is and you have yourself a good runner.

 

[CharlesS]

Check the Manifold Absolute Pressure sensor that is attached to the throttlebody towards the back. It is attached to the TB with two screws and has a small rubber hose which is hard to see that senses TB pressure while starting and running. There is a harness connected that will unplug.
Check the condition of the hose and ensure the connector is snug and the terminals are dirty.
There is also a chance that the fuel injectors are leaking by due to dirty injector pintels.

 

[PDXGraham]

checked the MAP and it has 4.59 volts with the key in on position and 30 ihg of vacum. dont know what it is at idle cause it wont start do to too it flooding itsealf

 

[91to99]

I had a '91 that was flooding because of the coolant temp sensor...
Just a thought.

 

[PDXGraham]

MAP sensor -Checked (fine)
NSS - Checked (fine)
TPS - Checked (Fine)
CPS - Checked (Fine)
CTS - Uncheckd
Fuel presure - Checked (fine)
has spark
had good fuel

 

[PDXGraham]

also its not throwing any codes

 

[Shorty]

compression check it to verify the valves and pistons/rings are capable of creating sufficient compression. It's possible the PO overheated it and burned a valve (or more) and the lack of intake vacuum is telling the MAP sensor to correct for low vacuum with more fuel.

 

[PDXGraham]

good compression, around 125lbs on all 6 holes

 

[J Pugh]

So, it runs well when not idling?

Replace IACV.

 

[yardape]

Everything you've written sounds like an IAC valve needs to be cleaned or replaced.

 

[PDXGraham]

at least i have narrowed it down to a fuel delivery issue, its getting too much and thats why it wont start and idle well.

 

[J Pugh]

at least i have narrowed it down to a fuel delivery issue, its getting too much and thats why it wont start and idle well.

How did you come to this conclusion?