67 GMC

I doubt it will help. If you really have fuel pressure on the rail that is steady, that check valve would only make it easier to start the next time you start it. It won't impact your engine while running. If you tried the off/RUN/off/Run technique and it's not starting quicker, you don't have a priming issue. Your CPS could be weak. Your battery might be getting low from all this extended crank and the starter may not spin fast enough to hit the minimum RPM.


Did you check the MAP sensor hose to make sure it's going into the throttle body and isn't blocked or cracked? Did you take off the throttle body air hose to see if it's carbon-ed up? Something is basically is wrong.

matt0106

I've recently checked the CPS voltage at the ECU connector, and it almost instantly jumps to .45 of a volt, then higher after that. I'm thinking fuel delivery problem. So replace, fuel filter, FPR, then fuel pump, right?

67 GMC

If you have pressure at the rail, and it increases when you remove the vacuum line from the FPR, then you most likely do not have a fuel pump, FPR or fuel filter issue (at least that's not the problem causes the long cranking).


A weak fuel pump would cause it to start on prime but you would have erratic performance (like stalling, backfiring etc). If it was completely bad, it wouldn't start or run. If the fuel pump is making the right pressure at the rail (and you said it was), then your long crank time is caused by something else. I'm still thinking CPS but that's just based on my experience. Try pulling the coil, cleaning the contacts and re-seating.

67 GMC

How did you check the voltage of the CPS? Was the meter set to AC or DC Volts?

matt0106

It was set to AC.
I'll pull the coil after I get off.

DFlintstone

Have you checked your MAP tube? Also, if you keep it floored does it start faster?

There is a brittle little tube. It comes out of a rubber plug, low on the engine side of the throttle body. It runs back to the firewall, then up to your MAP sensor sort of high up there near center on the firewall. CRUCIAL!! The MAP will tell the ECU to dump fuel with less/no vacuum. Any crack or blockage there and you will not be happy! Very important that.

matt0106

So, I bought a new coil. Helped a little bit.
Cleaned the spark plugs, may have helped a little bit, not sure.

I will check the MAP sensor later today, I have one from a JY Cherokee, hopefully it'll work. I think the vacuum line on it is fine, but I'll double check.

matt0106

Ok, I really appreciate the help from DFlinstone and 67GMC, but come on guys, no one else can chime in and help? Cruiser54, where's your input? I know you used to work on them, so you gotta have some.

I've checked pretty much everything that has to do with spark, fuel and air, so I'm freaking stumped. MAP sensor didn't help. Should I switch back to my other ECM?


I just need to get it to start how it should, and to stay running and not die out.

matt0106

Come on guys. I need more fresh ideas from people who may have experienced this too.

matt0106

Compression loss?

DFlintstone

We start Jeeps without depressing the petal, you just turn the key. (no throttle)

With Renix, (and likely HO), if you hold the petal flat on the floor it cuts off injector pulse. This cuts off fuel and provides max air to get out of a flooded condition. You tried that?
Waz not worried about the map sensor, just the tube and it's wires. I might try unplugging any or all under the manifolds so it might work on default settings. Be ready to put them right back when that does not work.......

matt0106

Thanks DFlinstone, yes the MAP sensor vaccum tube is fine. I have not tried holding the pedal yet, I will next time. It's now 1:10am where I'm at, so it'll be later today. Thanks.

lunghd

Fuel smell... 'could' be leaking???

I wouldn't do anything else until I FIXED the source of that fuel smell. Costs nothing but time to trace the fuel system end to end. O rings are cheap... a leaky injector not so cheap but still a lot less than a fire.



What's that smell?...

matt0106

There is a fuel smell ONLY while cranking. After it starts it doesn't smell anymore. I think I has something to do with my exhaust manifold leaking.

DFlintstone

Did you try holding it floorboarded? Does doing the poor mans prime change anything? YES! X2^, look for leaks, including the injectors themselves.