My '88 xj will not start first time ever.

My '88 will not start. Its a 4.0HO, 5 speed and it used to start up, idle a little higher than normal and kick down after a few seconds. Today it tried to start up, you can hear it getting air through the k&n and it dies after a second. I tried to start it with the clutch engaged and without with exactly the same result. This has never happened to the rig since it was bought in 88 brand new. It does have a new 2 row radiator and I got rid of the surge container and upgraded it to a '92 or better. Why won't it start? Throttle Position Sensor? Please Help Guys.

Probably, your CPS, I had similar problems and replaced the CPS and don't have them anymore. It is an easy swap, but the part isn't very cheap. Best thing is to take it to a parts shop and have them test it with a multimeter, unless you know what you are doing you can test it your self. Do a search for "CPS voltage" and you can find out what it is suppossed to be.

zak8642 said:

it dies after a second.

Click to expand...

'Sounds like a fuel pump ballast resistor/circuit problem to me. If it doesn't run AT ALL, then probably the CPS wiring/connector. Hard to tell what you mean by "getting air through the K&N.

Nothing wrong with closed cooling but some people have a better time understanding the more conventional open system.

i second that i had the same problem... if you jumper pos batt to the back end oof your ballast resistor (the side that continues on to your fuel pump (the rear most of the 2 connectors) try that and cranking it...

Air+Fuel+Ignition. Ok there's plenty of air most times. So it's fuel or ignition. Of these ignition is the most easily tested. Use an old spark plug. Plug it onto one of the plug wires and secure the threads to the block somewhere. (Holding it against the block is for the braver among us but it can be done) Crank. See regular sparks? If no then I'd guess this is the problem. If yes then try the fuel side. Turn ignition on. Hear the fuel pump come on for a bit? Turn off ignition. There's a pressure test port on the fuel rail. It has a cap which when removed reveals a tire valve stem like valve. Press it, being careful that the fuel that will squirt out doesn't go in your eyes or ignite. (Or use a fuel pressure gauge - the approved way) Any fuel pressure?

If no spark, I'd replace CPS (about $60), if still no start I'd replace coil (about $40) If still no spark I'm outta ideas. I had the no-start problem recently and gave up after the CPS. Shoulda kept going thru the coil since the dealer I took the Jeep to charged me $250 to toss one in (*&&%^$#$!!) After you've swapped the coil with no luck then things can get very hard to troubleshoot.

If no fuel then time to hunt the fuel pump circuit or the fuel pump.

If it seems you have both spark and fuel and the engine runs for a bit and dies, I'd still do the CPS. Life is tough on this particular sensor and it should be done just to get better reliability from your Jeep. My CPS on my '92 was operational but careful inspection of it showed that the wire insulation where the wire enters the sensor was gone and the copper exposed. Just a matter of time until it would have died so I'm not unhappy at swapping a new one for one that was working.

I can tell the jeep is getting air, and its getting gas. It has never had a problem since '88. 17 years 215k many off road miles. Good advice you guys kick A@@!!!

Zak

jumper your ballast resistor 1st it wont cost u anyhting... i had the same exact problem on mine... if it works... its either your ballast resistor its self (common prob) which u cna bypass at the cost of a noisy fuel pump or replace... if its not the ballast resistor then its a wiring issue.. and we got to brake out the wiring diagrams.

It tries to start, gets air and gas and then dies. It starts for about 1 second every time. For years it would start up, idle a little high and kick down.
Help me.