Hey guys, new here. So I have looked and looked through this forum for no start help. And I have found a ton of information but none so far that fits my exact issue. I have a 1990 dodge d150 with a TBI 5.2. One day it just stopped running and wouldn't start. It cranks and tries to start but will not. I checked fuel pressure coming into the TBI and I get 50psi. Coming from the fuel return out of the TBI I have 14.5. We replaced the distributor, cap coil and rotor. There is spark and there is fuel. The spray from both injectors is uniform and has a nice cone. I don't believe it to be a fuel issue at all. I can use starting fluid and there is no change.

I checked timing, rechecked TDC, unplugged coolant sensor on intake manifold. I used a meter and checked the TPS and everything seems to check out ok, but again it will not actually start and run. It will fire and try to start continuously but just wont actually run. The IAC seems to be working it moves while its trying to start.

I can unplug the injectors and just use starting fluid to double check that its not an over or under fueling issue but the result is exactly the same.

I also wanted to add there are no codes showing up at this time at all. I have even tried to disconnect the negative cable and reconnect to see if there were any changes without any luck.

I have researched and researched but i can find no spark issues, no fuel issues, ads issues and so on but like i said so far nothing that fits this scenario. Thank you for any help you can provide. I don't want to throw money at it just to see if I find a fix.

 

I'd check the cam and crank position sensors. If you're getting fuel, you're not getting spark. If you have a bad sensor, the computer will be waiting for a signal and not getting it. If it gets the wrong signal, it can set a code but if it's waiting, it won't have one.

 

It doesn't have any. Did you check compression? If you have spark and fuel it has to be in the motor. Did you take a plug out after trying to start it to see if has to much fuel(plugs wet from gas)? You said you checked timing where was it firing at?

 

I have not checked compression yet, that was my next course of action. It just seemed odd to me that it was all of a sudden. I apologize when I said I checked timing I meant I checked to make sure the distributor was lined up with #1 cylinder. I haven’t get the truck to run so I haven’t put a timing light on it. The Hall effect sensor is the only sensor it has for the computer that I know of for it to pick up and it was new in the distributor of course. I will check compression and see what I get later today. Yes I have pulled the plugs and though I can smell gas the plug wasn’t wet. I figured due to it not firing correctly the gas smell seems normal

 

If it's TBI, isn't 50 PSI just a bit high for fuel pressure??

 

That’s the incoming fuel pressure before the tbi. If I’m correct that’s perfectly normal pressure as it’s a pass through system.the pressure regulator regulates pressure into the tbi and the extra is returned to the tank. I could be wrong but that was my understanding of it

 

How did you test pressure? Just unscrew the feed line, and put a gauge on it?

When you crank the engine, do you see fuel being injected??

 

Yes I put a pressure gauge on the supply line to the tbi directly to a gauge. Then I put the gauge on the return side and it read about 14.5. Yes as it’s cranking the injectors show a nice strong cone spray. No drips or anything that looks out of the ordinary. Like I said it tries to start and gets really close to actually running. But just won’t quite get there it’s odd to me

 

Try holding the gas pedal on the floor while cranking. See if it starts.

 

I have done that as well with no different result. I have actually pressed the accelerator from just a little to wot just to see if there is any change and I have found none