Very intermittent no start

El Ed

Well-known member
Apr 20, 2004
309
11
San Diego
Check spark when it does it. The coil or the distributor is more likely to be the problem. Since you hear the pump run, seems a stretch to think it doesn't make pressure intermittently.

My guess too. Just went through this.. so you have spark? If you don?t start checking coil first, distributor rotor, finally if those two are good mostly likely the ignition module is toast. I just changed mine out after multiple days of no start in the trail and testing everything spark related. My NAS 110 still had the original ignition module dated 1992. Also adjusted air gap and timing. If you have the old 2 pin module you?ll need the 3 to 2 pin conversion cable. Good luck!
 

fishEH

Well-known member
Jan 26, 2009
6,927
201
Lake Villa, IL
So it sat for 2-3 weeks. I tried to start it Sunday, it kinda stumbled once or twice but would never catch and run.
I swapped the coolant temp sensor(the one with the rectangle plug) and spliced in a new plug since the old one was partially broken. Still no luck.
I pulled the fuel pump fuse and cranked it. It eventually caught and started and ran. I got out of the truck and walked around to reinstall the fuse but it died just as I went to put it in. I'm guessing it ran out of fuel since the pump wasn't running. I reinstalled the fuse and cranked. It fired right up and ran. Tried it again last night and it fired right up.
I wonder if its what BDM suggested, the return valve on the fuel sending unit?
 

El Ed

Well-known member
Apr 20, 2004
309
11
San Diego
Truck wouldn't start today. No amount of fuse pulling helped. It sounds like it almost wants to catch the second I stop turning the key to crank it.
This the ignition module referred to?
https://www.roverparts.com/Parts/STC1184

Yup, thats the one! Check the connection ends for any corrosion and make sure you have the correct cable otherwise you'll need the 3 to 2 pin connector.
So, do you have spark or not?
 

Grenade

Well-known member
Oct 8, 2015
111
6
Vegas
So, I have been battling somewhat of a similar problem, but mine has a problem of the Fuel Relay dropping in and out. I have trouble shot the issue to the Ground from the ECU is not able to hold the load on the coil side of the relay. This can happen at almost any time and its somewhat frustrating. Sometimes it is hard to restart but then other time it starts right up with zero problem afterwards.

I have a newer GM fuel pump in it that runs great, I wonder if the load on the fuel pump is more than the relay can hold. I've swapped the relay with others that are known to be good, but it seems the problem just follows it over. I have a new Bosch 40 amp relay that I will try but its been good lately since I installed a waterfall diode on the relay. `

Mine is a 95 which should be close but if you have any questions just PM me and ill be glad to answer.


I just wanted to update my post, I swapped in a JY ECU and have had zero starting / fuel pump relay circuit problems since.
 

fishEH

Well-known member
Jan 26, 2009
6,927
201
Lake Villa, IL
Yup, thats the one! Check the connection ends for any corrosion and make sure you have the correct cable otherwise you'll need the 3 to 2 pin connector.
So, do you have spark or not?
Haven't had a chance to check that yet, but its on my list.


I just wanted to update my post, I swapped in a JY ECU and have had zero starting / fuel pump relay circuit problems since.
That's interesting. As I mentioned it seems like it ALMOST wants to catch the split second I let off the key to stop cranking.

I'll start by checking for spark when cranking. Then try swapping in a spare ignition module. Then try a spare ECU.
 

llamasayswhat

Member
Nov 30, 2017
21
1
Kailua-Kona, HI
Have you changed the ignition rotor recently? If they are the same as the RRC, essentially every single modern production unit is absolute trash. Your best bet is to locate a good old unit
 

fishEH

Well-known member
Jan 26, 2009
6,927
201
Lake Villa, IL
I haven't changed anything recently. Did plugs and wires last July.
I pulled a plug wire and installed a used plug and laid it on the valve cover. Had my daughter crank and confirmed I have spark.
I may have to look at the fueling issue. Is there a way to check pressure on a 94 without a schraeder valve?
 

fishEH

Well-known member
Jan 26, 2009
6,927
201
Lake Villa, IL
So Friday I went out and tried it. Did not start initially, but sounded promising. I know that's vague but its hard to explain. Pumped the gas a few times while cranking and it chugged once or twice like it was closer to starting. Then I cranked it again, this time I pumped the gas pedal repeatedly very quickly and it finally stumbled to life! Saturday and Sunday it fired right up, no pedal pumping needed.
Seems like a fueling issue at this point. Pretty sure I replaced the filter last summer. Non-AEL pumps are pretty cheap so I may just look at replacing that.
 

fishEH

Well-known member
Jan 26, 2009
6,927
201
Lake Villa, IL
Possible flooding from sitting? Stuck open injector? Did it reek of raw fuel after it fired/smoke?

Maybe, IDK. It started up yesterday no problem. Its supposed to rain today so I'll try starting it again tonight. Then again tomorrow. Then I'll let it sit for two days and give it a go. Try to develop some sort of pattern.
 

fishEH

Well-known member
Jan 26, 2009
6,927
201
Lake Villa, IL
So I've been attempting to start it every day for a while now.
When I turn the key to Position II and let the fuel pump run first, it will sometimes start with considerable effort, or not at all.
However, if I turn the key quickly from off right past Position II directly to cranking its fired up quickly every time so far.

So it seems like an overfueling problem. I just need to figure out the culprit.....
 

BDM

Well-known member
May 23, 2005
333
30
OR
Sorry, just catching up on this...

So mine had similar issues. I would crank and crank and no start. Sometimes it would be really close and giving it gas would suddenly bring it to life. However, the biggest clue was letting the key sit in the 2nd position where I could hear the pump running. If I let it sit there for 5-7s and then cranked it, it would start right up. That also told me it’s probably fuel related. All my relays were tested fine. Starter etc.

Not sure if you have an AEL or non but the AEL pumps are obviously more expensive . Tillery thought it sounded like a fuel issue and had a vote of confidence from him it was most likely the return valve in the sending unit itself.
 

BDM

Well-known member
May 23, 2005
333
30
OR
So I've been attempting to start it every day for a while now.
When I turn the key to Position II and let the fuel pump run first, it will sometimes start with considerable effort, or not at all.
However, if I turn the key quickly from off right past Position II directly to cranking its fired up quickly every time so far.

So it seems like an overfueling problem. I just need to figure out the culprit.....

Man, I jumped the gun too quickly with that last post! Mine obviously had different symptoms. Do you have a good used fuel pump assembly you could test?
 

fishEH

Well-known member
Jan 26, 2009
6,927
201
Lake Villa, IL
Man, I jumped the gun too quickly with that last post! Mine obviously had different symptoms. Do you have a good used fuel pump assembly you could test?

Yeah its weird. I've owned a handful of D1's and I'm pretty accustomed to putting the key in Pos II for a few seconds prior to cranking. This truck seems to need the exact opposite. Finally figured I need to diagnose it with the help of a fuel pressure gauge. Just need to get one installed which is kinda a pain since my 94 doesn't have the Schraeder valve on the fuel rail.