jeffasmi

My 1990 cherokee laredo turns over but will not start. I got it started with starter fluid spray and put fresh gas in (1/2 tank). It ran smoothly but after I turned it off it still didn't want to start. What should I start with?

tjwalker

Check for spark. Pull a plug, keep it attached to the plug wire, place the plug electrode near a good engine ground. Have a buddy crank while you watch. You are looking for a strong, BLUE, snapping spark. Yelow/orange/white indicates a weak spark which may be a faulty ignition coil.

If you have GOOD spark, then you have a fuel delivery problem. For a 90, you need approximately 31 psi of fuel pressure to start the engine. Verify with a gauge, which you can rent from many big box parts stores.

Good luck and let us know what you find!

Monstereagle79

Maybe the crankshaft position sensor also.

jeffasmi

Well I went out to work on it but thought that I would try to start it first and the darn thing started. So I drove it around and checked the tires, got back home and turned it off and then tried to restart it and it wouldn't start. What do you think? It turns over fine, just doesn't quite get started.

jeffasmi

I saw on another post where someone uplugged/plugged their MAP sensor. Could it be that on a Cherokee?? Where and what is a MAP sensor?

1990xj2d

im having the same issue on my 90 xj 2 door what used to work for me was unplugging the IAC waiting a couple a seconds and plugging it back in i replaced mine didnt fix my problem when you have the starting issue try turning your key on but dont start it wait a couple a seconds then turn it off do it a couple times if it starts its most likely the fuel check valve there a couple of threads that have info on this if you search for them

jeffasmi

I removed the crankshaft postion sensor connection, then put it back on (without replacing the sensor) and it cranked. (two times). Sensors probably going bad so I'll replace it and hope thats all it was.
I have a 90' and 96' cherokee and the 90 sensor is much easier to get to than the 96.

Thanks for all the suggestions!!

tjwalker

Buy your crank sensor from Jeep. Trying to save you from heartache down the road.