knever3 Posted February 25 Share Posted February 25 I have had so much trouble with this, full backstory. 4.7L stroker, 99 intake, BBK throttle body, Hesco TPS adapter It has struggled to idle at a constant speed, hunting up and down RPM from 300-800 RPM, can't confirm unless I hook up my MT2500, just gauge reading. It seems to be worse in the winter months, I use remote start and let it idle for 20-25 minutes to warm up for a 6 minute drive LOL I was tired of it so I turned the allen screw to increase the RPM at idle and it doesn't surge that I notice anymore. Now the idle is too high, about 1k and I don't like it. Turned it back down and it takes 10 seconds to start, like it is not firing the ignition and you need to pedal it to get it to start like a carb. I want to set the idle screw correctly and remove/clean the IAC again. I've replaced it years ago, but never solved the problem. I have worked with grounds everywhere, measured the TPS voltage several times. I have not checked the AC voltage for the CPS yet. Where do I go from here? I always thought it was temperature related, but who knows. Link to comment Share on other sites More sharing options...
Eagle_SX4 Posted February 25 Share Posted February 25 23 minutes ago, knever3 said: I want to set the idle screw correctly and remove/clean the IAC again. My understanding is that screw is not an idle adjustment screw. It is a throttle blade stop screw. It should be adjusted until the throttle blade is fully closed but not scratching the walls of the throttle body. The IAC is what controls the idle speed. Link to comment Share on other sites More sharing options...
knever3 Posted February 25 Author Share Posted February 25 Had 5 minutes, re-adjusted throttle plate stop to just rest on the screw. Hooked up fuel pressure gauge and cycled the ignition several times. No fuel pressure, check valve on pump bad. When it did run my reading was 23psi, should be 45 and it did not go up when throttle applied. Bummer, this pump lasted 15 years. Link to comment Share on other sites More sharing options...
Eagle_SX4 Posted February 25 Share Posted February 25 10 minutes ago, knever3 said: Had 5 minutes, re-adjusted throttle plate stop to just rest on the screw. Hooked up fuel pressure gauge and cycled the ignition several times. No fuel pressure, check valve on pump bad. When it did run my reading was 23psi, should be 45 and it did not go up when throttle applied. Bummer, this pump lasted 15 years. I don't think your fuel pump is dead. That gauge is reading 28 psi not 23. Cycling the ignition will get the pump to come on only after sitting for a few minutes. Fuel pressure should be checked with the engine running. 31 psi with the vacuum hooked up to the fuel pressure regulator and 39 with the vacuum line removed. Link to comment Share on other sites More sharing options...
knever3 Posted February 26 Author Share Posted February 26 I cycled the ignition listening for the relay to click. The gauge never moves until I cranked, then it would immediatly drop back to zero. Link to comment Share on other sites More sharing options...
pizzaman09 Posted February 26 Share Posted February 26 Link to comment Share on other sites More sharing options...
llhat Posted February 27 Share Posted February 27 23 hours ago, knever3 said: I cycled the ignition listening for the relay to click. The gauge never moves until I cranked, then it would immediatly drop back to zero. How about your fuel pump resistor, is it bypassed? When the start solenoid is engaged (behind battery under the plastic electrical cover (beside the coil), there is current directly placed to the fuel pump, bypassing the resistor on the drivers side fender (beside air box). its terminal is at the top of the start relay, you can power the pump from that wire by unplugging it and applying +12v to the wire. Link to comment Share on other sites More sharing options...
knever3 Posted March 3 Author Share Posted March 3 I temp. bypassed the ballast resistor, no difference. I didn't check voltages though. I ordered a new replacement Bosch fuel pump from ebay. It was supposed to arrive Friday, then Saturday, now, who knows when. USPS sucks. I will do some more testing before replacing again. I installed that pump in 2016, so it's not that old. I can't believe I couldn't find that Bosch 69302 pump anywhere, I bought it on Amazon and I remember back then no one could order it. Maybe it's been superseded and it has a new part number. Again, no one had the pump so I had to order one off ebay. By the way, I am running a '95 fuel pressure regulator, so my fuel pressure was 45-49psi if I remember correctly, not the 39psi that the Renix runs. I am running 21lb injectors. I will update this once I replace and check the values later. Link to comment Share on other sites More sharing options...
knever3 Posted March 4 Author Share Posted March 4 I FINALLY got my Bosch fuel pump from ebay via USPS, albeit 3 days after I initially expected. The problem I see is they did the whole bait and switch. The pump and listing I ordered was a Bosch 69302, but the pump has no numbers that resemble this. The part number is 0580453473, and I can't cross it to the 69302. I am pretty bummed about this since I don't know if it is a replacement pump, and for the ebay seller to list as such. What should I do? I don't know the specs of this pump, nor do I know if it is a direct replacement for the 69302 I already have installed. On the ebay ad it shows a cross reference to the part number, but the pump has a smaller pickup and a tiny sock. I am VERY reluctant to put this in and waste my time. What would you do? This would be easy if a parts store could simply get one, or have one in stock. At least the truck still runs, for now... https://www.ebay.com/itm/145861307178 Link to comment Share on other sites More sharing options...
watchamakalit Posted March 4 Share Posted March 4 4 hours ago, knever3 said: I FINALLY got my Bosch fuel pump from ebay via USPS, albeit 3 days after I initially expected. The problem I see is they did the whole bait and switch. The pump and listing I ordered was a Bosch 69302, but the pump has no numbers that resemble this. The part number is 0580453473, and I can't cross it to the 69302. I am pretty bummed about this since I don't know if it is a replacement pump, and for the ebay seller to list as such. What should I do? I don't know the specs of this pump, nor do I know if it is a direct replacement for the 69302 I already have installed. On the ebay ad it shows a cross reference to the part number, but the pump has a smaller pickup and a tiny sock. I am VERY reluctant to put this in and waste my time. What would you do? This would be easy if a parts store could simply get one, or have one in stock. At least the truck still runs, for now... https://www.ebay.com/itm/145861307178 Ouch. That sucks. Me personally I would send it back. You were hoodwinked and that's against ebay policy. Link to comment Share on other sites More sharing options...
knever3 Posted March 4 Author Share Posted March 4 I plan on sending the ebay one back, in my new research I found the LAST ONE on RockAuto. Google never seems to search their site, I don't know if it's an algorithm problem, or if it's because of their ladder structure to find items. For what it's worth, the actual Bosch fuel pump number to search for is 0 580 453 477. The number 69302 is nowhere to be found on the actual pump, I believe it's an internal number for Bosch to sell a "Package", meaning all the accessories including the hose, clamps, O-ring, pigtail, rubber grommets, etc. The pump number is 0 580 453 477, if you need any other of the parts to convert the old larger pump to a newer style, you need the whole package to do the install. What a deal/ordeal Link to comment Share on other sites More sharing options...
Eagle_SX4 Posted March 4 Share Posted March 4 The Bosch 69544 pump is a replacement for the 94 and 95 4.0 Cherokees. Link to comment Share on other sites More sharing options...
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