tj21 Posted June 8, 2011 Share Posted June 8, 2011 2.5L w/ TBI starts up fine while cold. If I drive it a while and it warms up, it is very difficult to restart. I finally figured out that if I press the gas pedal in all the way in to clear the fuel, it starts up good, even when warm, so I assume it floods. I have searched around for others having this problem, and it seems to happen on trucks that were sitting for long periods of time like mine. I have recently done these repairs without any affect on the flooding: Cleaned throttle body, new fuel injector, new O2 sensor, new cat converter & muffler & exhaust pipes, new spark plugs & wires & cap & rotor. What could be causing the flooding? Link to comment Share on other sites More sharing options...
duster1971 Posted June 8, 2011 Share Posted June 8, 2011 May not be flooding it culd be the distrib advancing to far and causing a hard crank. Holding the pedle down will not help unflood an engine. But flows more air. My ford did the same thing for a while. Link to comment Share on other sites More sharing options...
tj21 Posted June 12, 2011 Author Share Posted June 12, 2011 Still looking for tips on this problem. Link to comment Share on other sites More sharing options...
JeffN Posted June 12, 2011 Share Posted June 12, 2011 check coolant temp sensor for the ECU, if it is reading wrong it may attempt a "cold" start causing more fuel than needed to be sprayed into the motor. Link to comment Share on other sites More sharing options...
tj21 Posted June 20, 2011 Author Share Posted June 20, 2011 check coolant temp sensor for the ECU, if it is reading wrong it may attempt a "cold" start causing more fuel than needed to be sprayed into the motor. Can someone please help me locate the coolant temperature sensor on my '86 2.5L? I have looked for over an hour. EDIT: Found it just after posting this. Now how do I test it? Here's photos for the next guy locating the sensor: Link to comment Share on other sites More sharing options...
Zenobian_84 Posted June 20, 2011 Share Posted June 20, 2011 check coolant temp sensor for the ECU, if it is reading wrong it may attempt a "cold" start causing more fuel than needed to be sprayed into the motor. Can someone please help me locate the coolant temperature sensor on my '86 2.5L? I have looked for over an hour. EDIT: Found it just after posting this. Now how do I test it? Here's photos for the next guy locating the sensor: Now is the sensor located where the antifreeze is coming out of the hole in the 2nd picture? :hmm: Link to comment Share on other sites More sharing options...
tj21 Posted June 20, 2011 Author Share Posted June 20, 2011 Now is the sensor located where the antifreeze is coming out of the hole in the 2nd picture? :hmm: Yep. I took it out and snapped the photo while it was still draining. Link to comment Share on other sites More sharing options...
Zenobian_84 Posted June 23, 2011 Share Posted June 23, 2011 Now is the sensor located where the antifreeze is coming out of the hole in the 2nd picture? :hmm: Yep. I took it out and snapped the photo while it was still draining. Ah... I see. :thumbsup: Link to comment Share on other sites More sharing options...
kro10000 Posted June 23, 2011 Share Posted June 23, 2011 May not be flooding it culd be the distrib advancing to far and causing a hard crank. Holding the pedle down will not help unflood an engine. But flows more air. My ford did the same thing for a while. I'm unfamiliar with the 2.5, but on a Renix 4.0 holding the pedal at WOT kills the injector pulse, so it would in fact help starting a flooded motor. Link to comment Share on other sites More sharing options...
duster1971 Posted June 24, 2011 Share Posted June 24, 2011 I was unaware of the cut of in the injectorpulse in the renix system. I retract my previouse statement and apologize if I came across rude. Did the sensor help with the issue? Link to comment Share on other sites More sharing options...
kro10000 Posted June 24, 2011 Share Posted June 24, 2011 I was unaware of the cut of in the injectorpulse in the renix system. I retract my previouse statement and apologize if I came across rude. Did the sensor help with the issue? Didn't think you came across rude at all :cheers: I could still be wrong again as the tbi setup is different. Link to comment Share on other sites More sharing options...
tj21 Posted June 25, 2011 Author Share Posted June 25, 2011 I was unaware of the cut of in the injectorpulse in the renix system. I retract my previouse statement and apologize if I came across rude. Did the sensor help with the issue? I put in a junkyard sensor but it didn't change anything. The engine runs great, except for the hard starting after its been running a while. If I restart right away while its warm, it is fine. But if it sits for a few minutes (buying gas), there is no way it will start unless I clear the fuel with full throttle. Other symptoms that are likely related: Gas mileage is poor at 10 mpg, Failed emissions test with extremely high hydrocarbons. Keep the ideas rolling. Link to comment Share on other sites More sharing options...
cz777 Posted June 25, 2011 Share Posted June 25, 2011 check coolant temp sensor for the ECU, if it is reading wrong it may attempt a "cold" start causing more fuel than needed to be sprayed into the motor. the higher ohms the richer fuel or if open circuit dumping!!! please add air temp sensor both can life rough !!! Link to comment Share on other sites More sharing options...
tj21 Posted June 25, 2011 Author Share Posted June 25, 2011 check coolant temp sensor for the ECU, if it is reading wrong it may attempt a "cold" start causing more fuel than needed to be sprayed into the motor. the higher ohms the richer fuel or if open circuit dumping!!! please add air temp sensor both can life rough !!! Thanks for the tips. I tested both the MAT Sensor and Coolant Temp Sensor and the resistance looks normal under cold / warm / hot conditions. Also tested resistance for both to the ECU connector, including ground and sensor wires, and all is perfect. Now I can move on from these two sensors. Is it possible I have a bad ECU? I did emissions test again today and my HC = 9860 (max 220 allowed) and CO = 9.1684 (max 1 allowed). Link to comment Share on other sites More sharing options...
JeffN Posted June 25, 2011 Share Posted June 25, 2011 did you check fuel pressure? If your regulator isn't regulating it could blast past the injector causing a huge rich condition also Scope the ignition to make sure you don't have a faulty coil. Check the EGR valve and make sure it isn't sticking open telling the o2 sensor it's lean. Unplug the MAP sensor vacuum hose while running and see if the vehicle runs different and make sure it has vacuum at idle Link to comment Share on other sites More sharing options...
tj21 Posted June 27, 2011 Author Share Posted June 27, 2011 did you check fuel pressure? If your regulator isn't regulating it could blast past the injector causing a huge rich condition also My fuel pressure checks good at 15 psi. Scope the ignition to make sure you don't have a faulty coil. Still figuring out how to do this. Check the EGR valve and make sure it isn't sticking open telling the o2 sensor it's lean. EGR valve was shot. It was plugged and didn't move at all. Went to the junkyard and got another that seems to slide good since new ones are $100. A new gasket won't be in until Tuesday, but I put the EGR on anyway. Now my engine idles rough, and even stalls out sometimes. It did not affect the rough start while warm (I still think this is flooding, since wide open throttle makes it start up fine). Do I need to now look for an Idle Control Valve to fix the new idle problem? Could this be linked to flooding? Link to comment Share on other sites More sharing options...
64 Cheyenne Posted June 27, 2011 Share Posted June 27, 2011 Couple of places you might find useful info like a FSM or sensor diagnostics. http://www.greatlakesxj.com/tech.html http://www.lunghd.com/On_Site_Tech.htm Link to comment Share on other sites More sharing options...
tj21 Posted July 21, 2011 Author Share Posted July 21, 2011 May not be flooding it culd be the distrib advancing to far and causing a hard crank. Holding the pedle down will not help unflood an engine. But flows more air. My ford did the same thing for a while. Duster - I didn't pay much attention to this advice, but I finally looked at the distributor position while setting TDC for a timing chain replacement, and am wondering if you are on to something. Here's a picture of the pistons to verify TDC (head is currently off to get valve job and replace gasket): And here's the distributor position at same time. My finger is pointing to the mark I made at wire #1. Looks like the dist is advancing too far? How do I fix it? Link to comment Share on other sites More sharing options...
tj21 Posted August 15, 2011 Author Share Posted August 15, 2011 Still looking for help here. What causes the distributor to advance/retard? I have a FSM for my '86, and it says the rotor is supposed to be at 6 o'clock while at TDC (not at the #1 wire with most engines). You can see the above picture it is more at the 5:30 position. I removed the distributor and reinstalled rotating it one tooth clockwise. This puts the rotor more at the 7 o'clock position. It was hard to start, sounded like some backfiring, but once it went, it ran great. Definitely a leaner condition (probably too lean). Tried shutting it off and restarting, with same result, except it was harder to start. My third attempt it wouldn't start. I moved it back to the 5:30 position, and starts same as before, but runs rich. Then I found a 2.5L MJ at the junkyard. Set it at TDC, and the rotor was at exactly 6 o'clock. Here's the picture: I thought maybe my distributor was bad, so I bought the junkyard one. Installed it, and again could only install at 5:30 or 7:00. So appears the camshaft teeth are out of position. How do I fix this? Does the computer advance / retard the camshaft gear? That sounds odd, but I can't think of anything else. I did replace the timing chain, but had the same result before and after. I counted the 20 nails between crank & cam marks several times, and I'm confident I did not screw up the timing. Link to comment Share on other sites More sharing options...
tj21 Posted August 28, 2014 Author Share Posted August 28, 2014 FINALLY SOLVED! My comanche has been running very rich for a looooong time... I replaced the fuel pump a couple days ago, and she now runs great and easily passed emissions! Link to comment Share on other sites More sharing options...
Eagle Posted August 29, 2014 Share Posted August 29, 2014 Didn't think you came across rude at all :cheers: I could still be wrong again as the tbi setup is different. But the TBI system was still a Renix system, designed by the same engineers. I don't know, either, but it would not surprise me if it behaved just like it's big brother the 4.0L. Link to comment Share on other sites More sharing options...
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