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90 renix hard start

Old 04-14-2019, 04:24 PM
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Default 90 renix hard start

90 Cherokee. Starts fine when cold, Idles great, runs well. Soon as you shut it off it has hard time starting, acting like itís flooded, even when not run to op temp. Have to keep the pedal floored to clear it out. Grounds refreshed, connections refreshed, CPS is good, new TPS installed and adjusted, plugs, wires, cap, coil, etc. New MAP, fuel pressure reg, injectors good. Fuel pressure good and vacuum seems strong but not tested. Recently replaced fuel pump. IAC cleaned. Havenít replaced temp sensor yet, but leaning that way. If I can get this fixed and the brake lights to quit blowing fuses would be great little driver.
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Old 04-14-2019, 05:52 PM
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Brake light fuses can ruin your life! (long story). The "jiggle test" might help you there. If you can put a stick between the seat and petal to have them on, go jiggle some wires to see if somewhere blows the fuse.

Second.....try the fuel pressure drop test. If you have original injectors, they are crap. Even if you have replacements if some are leaking it will flood you and the pressure will drop too fast.
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Old 04-14-2019, 10:18 PM
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Thanks-got a 16 year old ďstickĒ to help hold the pedal down. Pretty sure a mouse got into the wiring. Replaced the injectors, and Iím not getting any fuel past the injectors when the key is off or itís not running. Just dumping it in while cranking. Had leaky injectors once before and the crankcase filled with gas. Bad bad bad. Fixed that though. Just thinking maybe the temp sensor isnít sending anything to the computer so itís assuming a cold start and dumping gas.
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Old 04-15-2019, 03:14 AM
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Hot soaking has hurt some of the injectors on these engines. It makes the liquid gasoline a gaseous gasoline and doesn't output right until enough gasoline has passed thru the injectors to cool it. Many wrap corrugate paper or insulation around the faulting one or all of them as well as some placing an heat shield around the intake itself to further dissipate the heat elsewhere.
From your description I would be inclined to believe that this is your problem. Having replaced the injectors wouldn't really solve the issue because new heat is created every drive.
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Old 04-15-2019, 07:59 AM
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check the integrity of the hose/pipe between the throttle body and MAP sensor.
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Old 04-15-2019, 10:16 AM
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Iíll check the MAP hose again but pretty sure itís sound and clear. Replaced it recently.
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Old 04-15-2019, 02:44 PM
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Cruiser is your guy here. I had an issue years ago which is way too long of a story. Pete, just to narrow it down maybe he could disconnect just the Engine Temp Sender from his puter and see if it runs OK on defaults? Heck, maybe the 02 also.

And indeed, I've seen it, that MAP tube indeed needs to be perfect. Any fault there and you are screwed. Between Crusier and other members here you are likely in a good place to add to your clearly not so modest knowledge to lick this.

The ECM can make it run OK without most of the sensors. Needs the MAP though. Other than that.........."without a sensor" is not the same as a mouse grounding a wire or connecting it to something else, is why I'm proposing eliminating a signal or two to your puter.

CPS is a tricky bastard also.

Last edited by DFlintstone; 04-15-2019 at 02:47 PM.
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Old 04-15-2019, 02:49 PM
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10-4. Will try that. Am familiar with cruisers tips-likely saved me tons of work and $$ in the past. Been lurking around these forums for awhile.
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