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89 Renix XJ warm engine no-start

1989AMCXJ

NAXJA Forum User
Location
Big Bear Lake
I have been researching this issue for quite some time now and can't seem to find a solution, so here it goes...starts cold perfectly. Runs perfect. Stop and let it sit, won't start. Wait for 20 30 minutes starts, but rough at first, then smooths out. If you crank it too much in the no start condition, it will flood out. And you will wait longer to get it to start once cold. New parts: all sensors are new. The entire fuel system front to back is new. New bad part? Maybe. Diagnostics all within range. Please help...


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Try cycling the key a few times before starting, if that fixes it then you have a heat soak problem. That is where the fuel in the rail basically boils off from the residual heat in the engine and it takes the fuel pump a bit to get the bubble through the system.

If not, I would think about the ignition module or coil. You can kind of test it with a squirt bottle of water. Get it hot to the point where it won't start, then spritz the coil/module several times to cool them off and see if that fixes it. If so you have either a bad coil or ignition module.
 
I had this problem on my 88. Turned out to be the ignition switch. Still could be a heat soak problem if the fuel pump check valve has gone bad or fuel pressure is low
 
Thank you both for a response. first off, the coil is about three years old, but I did replace the Coil module (made in USA). along with all relays and the starter relay. I do however have a new Delphi GN10155 Ignition Coil on order. Sometimes, at first, I could cycle the key, and after the fuel pump stops its initiation, it would start...but now it wont at all. I will try the squirt bottle approach, but if it is in fact a heat soak issue, any thoughts on a fix? to cwyman6, the entire fuel pump assembly is new, along with all high pressure injector fuel lines, pressure control valve, and 3gen bosch four hole injectors.
 
With good components, you should not have heat soak. So if you find a component that works after you cool it down, replace it.
 
I had the exact same symptoms on a newer XJ. Cold, started and ran fine. Warm, stop and go into the store, come back and it either wouldn't start or ran like crap. Acted like it was flooded.

Ended up being a bad temp sensor. It was causing the computer to think the engine was cold even though it was up to operating temperature.

Just a thought. Makes more sense than an ignition switch issue.

dub
 
Dubster: both temp sensors are under 90 days old, and I have a REM + reader that reads out the temps along with the factory gauges, and all seems to be well...I am going bonkers with this!!!
 
Need to check power at the icm when cranking. The contacts go bad and after it runs for a while the resistance in the switch can pull to much power causing a weak spark. You can bypass it by putting power to the correct wire coming from the ignition.
 
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