1988 jeep Cherokee fuel problems

88jeepproject

New Member
Joined
Feb 3, 2016
Location
Aberdeen
Put 2 fuel pumps in and some how something keeps killing fuel pump getting a loud whine on them replaced ballast resister and cleaned fuel pump got a hesitation on acceleration
 
hey bud, we talked earlier. have you checked what the voltage is when it's running at the pump...the starter relay (by the battery with tons of wires on it) feeds the ballast resistor then the resistor feeds the pump lower voltage once running...could be that starter relay spiking voltage to the pump maybe but honestly, as many 88 XJ's I've had, I've never had one with same fuel pump issues (go figure) but at least 9 outta 10 have em. It usually end up being wiring issues and most people like myself with current jeep just rewire the pump circuit but go through your grounds, ground at the pump too, your battery terminals good and clean/tight, and check the actual wires to the pump that run along floorboard drives side. I hope someone else has a better suggestion but once you start tinkering with it, usually something don't line up with volt-meter and resistance checks. (the very bottom prong on the starter relay feeds power to fuel pump/resistor so check that with key on for 12v and once running, shouldn't be but 6-7v going to the pump)
 
sorry been gone all weekend bud...3-4 is too low so that toggle switch should work just fine. hope things work out with it!
 
Now still getting a hesitation on acceleration and idling weird done a full tune up gap plugs at .35 changed fuel pump again fuel pressure regulated fuel filter any suggestions
 
try adjusting your TPS... look it up on forums, there are tons of Renix sensor tests and adjustments that explain them better than my english would lol.
 
Champion or Autolites, not sure about Motorcraft but also wouldn't be the plugs unless they were WAY WAY off and terrible shape. I've seen jeeps with some pretty bad original plugs and still run fine. when you say "backfire" ...out the exhaust or through the airbox?
 
remove the distributo cap and check the amount of play in the distributor. I have seen a good few that neede new distributors installed because the gear gets worn
 
I'm starting to think the coil...I've changed 3 in the past few months on renix jeeps and they had very similar running issues. Coils on these are cheap to replace and in my experience they don't stop all at once, they usually break down like your describing. Coil and Ignition Module under it along with CLEANED up grounds (adding one usually too) and proper adjusted TPS are the very top 4 that will make a Renix run like it should. Having this said, electrical gremlins love to make a home in these jeeps in the simplest to the most hassle of ways so taking a volt meter to every major sensor for proper voltage and ground is usually a very good idea!
 
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