fire797 Posted July 2, 2016 Share Posted July 2, 2016 So I took the truck for a test run today. I live in las vegas. mild temps today water temp up and down around the 210 mark. just change to an open cooling system and that seems to be doing its job. However at a stop light the truck just died.... won't turn over..... truck sits for about 20 mins while my wife comes and gives me a jump ( new item to by jump box!!!!). truck starts runs for about a mile dies again. I can pour gas in the throttle body it starts then dies. this tell me I have spark and I check to make sure I have fuel pressure and I do. so this tells me the injectors are not firing.... Can someone tell me why?????? Link to comment Share on other sites More sharing options...
HOrnbrod Posted July 2, 2016 Share Posted July 2, 2016 When is the last time you have changed your fuel filter? Have you checked fuel pressure with a gauge at the fuel rail port? And what are you driving? Link to comment Share on other sites More sharing options...
fire797 Posted July 2, 2016 Author Share Posted July 2, 2016 all new fuel system tank to injectors..... 1989 Comanche and I have great pressure I used a bottle cap to get gas from the test port to put in the throttle body...... Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 2, 2016 Share Posted July 2, 2016 Won't turn over = won't crank = starter isn't turning = not a fuel problem. I'm assuming you mean it will crank, but will not fire or run? Link to comment Share on other sites More sharing options...
fire797 Posted July 2, 2016 Author Share Posted July 2, 2016 correct dirty Comanche.... it starts if a pour gas in the throttle body........ Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 2, 2016 Share Posted July 2, 2016 Try bypassing the fuel pump ballast resistor, it's a white porcelain block with two wires and a mount bolt, on the driver's fender up front, by the EGR solenoid thinger and airbox. Just pull the two connectors off and shove them together with some bailing wire or something. I wouldn't say I'm on the right track with that, but it takes 5 seconds to do. Link to comment Share on other sites More sharing options...
fire797 Posted July 3, 2016 Author Share Posted July 3, 2016 I have great fuel pressure...... what controls my injectors????? why do I have spark but no injectors???? Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 3, 2016 Share Posted July 3, 2016 I'm not certain, but do Cruiser's ground cleanups and such, check the CPS output for the sake of it, and maybe verify that the MAP and IAT are ballpark correct, because if you have spark and the injectors are not firing at all it isn't good (broken wire, bad ECM, maybe some things I don't know about). Link to comment Share on other sites More sharing options...
sinkrun Posted July 3, 2016 Share Posted July 3, 2016 Maybe broken wire/soldered joint in the engine wiring harness. Link to comment Share on other sites More sharing options...
buckwheat Posted July 3, 2016 Share Posted July 3, 2016 People often jump the gun on a 'broken wire'. Start with the basics and move up from there. Refresh all your grounds. Do the main Cruiser tips. Check CPS output. Get actual fuel pressure (true PSI measurement) at the rail. Then move on to a noid light. After that you can start worrying about the bigger things, like a possible wire break somewhere in the wire loom I know it is frustrating, but start at the beginning so we can make sure the foundation is good. Then if the problem persists smarter people than me will chime in with ideas. Link to comment Share on other sites More sharing options...
gogmorgo Posted July 3, 2016 Share Posted July 3, 2016 I have great fuel pressure...... what controls my injectors????? why do I have spark but no injectors???? You don't know you have great fuel pressure unless you've measured it with a gauge. Rent one for free at your preferred parts chain. I believe on a Renix the injectors get their signal from the sync sensor in the distributor, but the computer can recognize the failed sync sensor and will compensate so in most cases a failed sync sensor isn't noticeable. Rent the fuel gauge. Link to comment Share on other sites More sharing options...
Rockfrog Posted July 3, 2016 Share Posted July 3, 2016 ..... truck sits for about 20 mins while my wife comes and gives me a jump ( new item to by jump box!!!!). truck starts runs for about a mile dies again. I can pour gas in the throttle body it starts then dies. this tell me I have spark and I check to make sure I have fuel pressure and I do. so this tells me the injectors are not firing.... Can someone tell me why??????Two simple checks ... 1. Check fuel pressure (pressure should be 30-31psi with the regulator connected and 39psi with it disconnected). 2. Run a jumper on the ballast resistor (white block on inside of drivers front fender - wires are orange with black trace). If the filter is right plugged, or the ballast resistor is NFG ... You describe the exact symptoms. With a dead ballast resistor the pump will prime the rail, then once the engine fires, power for the pump is routed through that resistor. You get about a period of run time and then she'll stall out. A fuel filter is cheap if you haven't replaced it, may as well now so it can be checked off the list. Edit - you mentioned you already changed it, cross that one off. Have you tested the EGR system yet? If it's opening when it shouldn't it'll stall the motor as well. Disconnect and plug the vacuum line for it. Add a piece of hose and add vacuum. Should see the diaphragm moving. It should be normally closed. Sent from my SGH-I337M using Tapatalk Link to comment Share on other sites More sharing options...
fire797 Posted July 3, 2016 Author Share Posted July 3, 2016 fuel pressure is good. when the truck cools down it starts right up..... I have cleaned the block ground checked the sensor grounds and did the upgrade on the CPS. I have found some play in the dizzy shaft both side to side and up and down.... Link to comment Share on other sites More sharing options...
fire797 Posted July 3, 2016 Author Share Posted July 3, 2016 rockfrog it will not fire at all it just turns over I have spark but no injectors GREAT FUEL PRESSURE...... fuel pressure is not the problem everyone...... I have the gauge and it is fine everyone.....I don't mean to be rude but we all need to move on fuel pressure is not the problem..... Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 3, 2016 Share Posted July 3, 2016 So this only happens when hot? It will run every time after it cools down? And it's definitely not overheating the injector rail or fuel lines and causing vapour lock? Link to comment Share on other sites More sharing options...
gogmorgo Posted July 4, 2016 Share Posted July 4, 2016 I also don't mean to be rude, but when this is your only description of having "great fuel pressure" it doesn't exactly inspire confidence in your testing procedure. I have great pressure I used a bottle cap to get gas from the test port to put in the throttle body...... Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 4, 2016 Share Posted July 4, 2016 I also don't mean to be rude, but when this is your only description of having "great fuel pressure" it doesn't exactly inspire confidence in your testing procedure. I have great pressure I used a bottle cap to get gas from the test port to put in the throttle body...... I missed that. Yeah. That doesn't work. Link to comment Share on other sites More sharing options...
fire797 Posted July 4, 2016 Author Share Posted July 4, 2016 i towed the truck home. the next morning it started right up. when i used the bottle cap the fuel came out with great pressure. it squirt all the way a crossed the engine compartment. i don't travel with my fuel pressure gauge. so imho i think the fuel pressure is great.... this is a heat problem that is stopping the injector from working..... Link to comment Share on other sites More sharing options...
HOrnbrod Posted July 4, 2016 Share Posted July 4, 2016 Fuel squirting out the Schrader valve doesn't prove anything except you have some pressure. Testing the pressure using a gauge is mainly to determine if your fuel pressure regulator is working correctly with and w/o vacuum. Do that first, let us know what the pressure readings are with and w/o vacuum, then we can move on. Link to comment Share on other sites More sharing options...
DirtyComanche Posted July 4, 2016 Share Posted July 4, 2016 If you don't want to test pressure, you can at least verify if the injectors are firing or not. The preferred method is to use a NOID light, or a test light, or a multimeter with fast reaction or frequency capability. Pull all the connectors off, hook the NOID light up to #1 (or whatever) connector, crank engine and observe consistent blinking. Same with a test light. A good (if there is such a thing) analog meter will throw the needle back and forth on DC voltage, a good digital meter will show the pulses on voltage (it's not super fast) or you can get a low frequency reading on it using A/C frequency. Or you can pull the rail off, leave everything else hooked up, and crank and see if any fuel is coming out. If you burn your truck/garage/house/neighbourhood down doing this, please don't blame me. Link to comment Share on other sites More sharing options...
gogmorgo Posted July 4, 2016 Share Posted July 4, 2016 Until you put up some numbers no one's going to believe you actually have tested your fuel pressure. We're just trying to help you solve your issue, but we can't help you unless you help us. You're talking to a whole bunch of incredibly helpful people with years of experience who know these trucks inside and out, but they will rapidly lose interest in helping you if you continue to ignore their suggestions or requests for more information. Pretty sure I could spit fuel all the way across your engine bay with just my mouth. At absolute most human lungs put out like 3psi. Just saying. Link to comment Share on other sites More sharing options...
cruiser54 Posted July 4, 2016 Share Posted July 4, 2016 Link to comment Share on other sites More sharing options...
fire797 Posted July 4, 2016 Author Share Posted July 4, 2016 Okay so the pressure is 30 psi. I have had it running for about 3 hrs in the garage with a fan blowing on the rad and the hood closed. temp is around 210. I cleaned the ballast resistor connections did the cps upgrade. .7 vac at the connector. I also replace my starter wire it had several bare spots in it. I also cleaned the ground connection on the block. as of right now the problem is gone. It starts slow but it does start. thanks for everyones help and I apologize if my frustration upset anyone.... This forum has help me fix many problems on this truck since I pulled it out of the desert 8 months ago. Thank you for your time...... Link to comment Share on other sites More sharing options...
cruiser54 Posted July 4, 2016 Share Posted July 4, 2016 Okay so the pressure is 30 psi. I have had it running for about 3 hrs in the garage with a fan blowing on the rad and the hood closed. temp is around 210. I cleaned the ballast resistor connections did the cps upgrade. .7 vac at the connector. I also replace my starter wire it had several bare spots in it. I also cleaned the ground connection on the block. as of right now the problem is gone. It starts slow but it does start. thanks for everyones help and I apologize if my frustration upset anyone.... This forum has help me fix many problems on this truck since I pulled it out of the desert 8 months ago. Thank you for your time...... Woohoo. Here's hoping. Great job on the electrical stuff. Link to comment Share on other sites More sharing options...
fire797 Posted July 4, 2016 Author Share Posted July 4, 2016 Link to comment Share on other sites More sharing options...
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