long starts

[canada cold]

I have a 94 chev g20 van non turbo It turns over about 30 times before it starts. New lift pump new fuel filter Took to 3 gm dealers and cannot find the problem only codes are 23-84-99 accelerator pedal position and gm says it is not related to long start problem. Glow plugs and relay are ok. New pump last April No fuel line leaks. No air in fuel system. This problem has been on going for some time Starts perfect when hot.

[diesel1995]

If i were you, i would check for possible fuel drainback, and operation of the lift pump as well. Also, although ive never experienced this, ive heard the fuel cap can cause untold problems on certain vehicles.

Not much, but i hope it helps

Jake

[mciaio]

I agree, check you fuel cap vent. As you fuel is used in your tank you need to replace the fuel with air. If you cap is plugged you get a vacuum in your tank that will pull all the fuel back from the injection pump while the truck sits. While the truck is running the lift pump over comes the vacuum in the tank. Leave you cap loose after you park the van one night and see if it happens.

[taznj63]

did the stealers i mean dealers check each glow plug to see if working?
Pull wire off of glow plug and check resistance from tab to ground. Should be less than 1 ohm...
If you do not have a meter use a test light (12v) connect wire to battery positive then touch probe to each tab on glow plug, if light lights, assume plug is good.
If you need good plugs that will not burn out use set from Kennedy Diesel called quick heats.
I have them and then work great.
When engine is cold, glow plugs should cycle on for 10 to 15 seconds, then off and on a few more times when warming up engine.
I had a vrey hard time starting my truck when cold, glow plug light cycled the way it should, but I found that 5 of the 8 glow plugs were bad...
GM 9G's... If you have them, get them out now cause they will swell up and be hard to remove.
Install quick heats asap...

Hope this helps...

[Kidd]

I would check the glow plugs, mine started needing a lot of cycles to start, all plugs checked out ok, but when I replaced them all, the truck fired right away. Only thing I can think of is perhaps the used plugs weren't heating up enough for cold start.
K.D.

[canada cold]

Took the glow plugs out and bench tested everyone and they are working perfect. The lift pump is new and I have ample fuel pressure to the pump. I cannot figure out the problem for long starts and as i mentioned it starts good when warm but if it sits for 10 minutes or so it goes through the same thing long start.

[ucdavis]

There are a limited number of things it could be. I'll list all I can think of:
1) Fuel. Need 6psi or so @ IP on start. Try a cold start w/the water bleed valve open. If you get fuel there immediately on first key-on (before cranking) then lift pump is OK. If it takes a bit, then fuel is sucking back & you need to check filler cap and/or lift pump.
2) Air. Self explanatory.
3) Fuel into IP. Fuel solenoid on a DS4 IP is the engine shut-off; if it doesn't kick open when you turn the key on (you can feel it "click" open or closed) then it is sticky & not allowing fuel into IP; if you feel it click open, its working.
4) Fuel injection pulse signal. You are not getting codes 35/36 so PCM isn't getting feedback of bad signal, but some have stalling or non-starting w/out codes associated w/improper fuel delivery due to grounds or connections the PCM isn't monitoring. Engine grounds on older vehicles can get intermittently functional & complete their circuits unreliably; undo, clean and brighten, & reassemble/tighten all ground straps from heads to frame, etc. to assure complete circuits. Also, the 15-pin connector by the fuel filter has given owners fits. You can clean the connector pins w/contact cleaner, & reconnect for assurance of connections.
5) Presumably the "Don't-worry-they-all-do-that" dealers checked engine cranking speed; if not, have that checked. You need two good batteries, & full charge to get started w/a diesel, especially when cold.
6) Glow problems. You've checked plugs; are you getting excessive white smoke on start-up? If no, then glow seems OK. If yes, glow cycle is not getting fuel hot enough for good ignition on start-up.
7) APP trouble. Accelerator pedal assembly is essentially 3 potentiometers or rheostats & PCM interprets the combined signal to assure it gives the IP the right signal for fuel delivery. You are getting codes of trouble here; this might be confusing the PCM on start-up. Clear codes, then try a cold start, & recheck codes after (regardless of easy or hard start). If codes reappear, I've read here on TDP of curing a bad APP by drilling a small hole in it, & hosing out the accumulated wear particles from the rheostats using contact cleaner or some other fully evaporative cleaner that can be applied under pressure; wash it out liberally then blow out using a needle-type air nozzle till you're sure its dry inside. Then seal the hole (J-B Weld or similar), & reinstall. Try starting.
8) Engine too cold. I believe all 6.5's came w/block heater; if its colderna YKW, & you are not using the block heater, run an extension cord & try it in the morning.
9) Fuel too cold. The Stanadyne Fuel Management system has a fuel heater in the bottom of the filter bowl. Maybe that is burned out (its supposedly about the equivalent of a 100 watt bulb) and fuel is somewhat gelled & not flowing properly. You can help this w/fuel additive. (I wonder about this on truly cold starts as fuel in the IP won't benefit from the heater which is 15" or so away by rubber fuel line, but that's just me, Stanadyne knows best.)
Maybe this'll spark some other things to try as well.

[chickenhunterbob]

ucdavis

That response belongs in the TDP hall of fame.

bob donogh

[tom.mcinerney]

UCDavis--
1: Affirm C-H-Bob's comment.
2: The fuel heater is activated when fuel below 40*F, heats to above 70*F. It makes life easier for FIP.
When fuel gels[wax 'crystals' clog filters/pickup screens] it's progressive--the engine will start, but exhibits fuel starvation because flow is inadequate. Other things equal, it'll start because at shutdown the FIP was primed. At moderate temps idling will warm enough to run fine. Depending on the fuel load and additives used, a point is reached(ambient temp low enough) when need more additive/more heat to operate. Typically it'll begin to gel around 19*F, be a big problem below 9*F. I have no experience with the -20/-30*F stuff!

[canada cold]

Thanks for your input guys. The vehicle sits in a heated garage at 65 degrees and cannot be a fuel tempature problem. It just rolls and rolls before starting. New lift pump. I will try the fuel pedal procedure next as I have had three codes come up for it. Cleaned all battery terminals and ground straps still no luck. I dont think it is compression as when the vehicle is warm and it sits for 5-10 min in the heated garage it rolls and rolls before firing. How do you take the fuel solenoid off the electronic standyne pump. Have tried almost everything to cure this problem. Tested oil pressure switch and it is fine.

[BERT]

DID THIS PROBLEM START WHEN YOU REPLACED THE IP

[canada cold]

No this problem did not start after the injection pump was replaced. It started in the fall. I took the van to a diesel injection specialist and he change the black box on the pump and that was not the problem. There is ample fuel pressure at the pump as the lift pump is brand new. No smoke when it does start. He said the injectors were okay and the pump shows no codes so every one is baffeled at the long start problem. Starter is turning over fast enough so that is not the problem. GM says fuel pedal has no bearing on starts but I am going to try unhooking it and see if the vehicle starts. I am pulling my hair out as in 2 weeks I hope to head to Florida and would like to put this problem to bed.

[ucdavis]

1) Thanks for the nomination & the second.
2) The fuel shut-off solenoid has either an allen socket or a hex-nut protrusion on top. It seals to the IP body w/an o-ring. CCW turn to remove; CW to tighten. Clean the area around base of FSO B4 removing, cuz you're opening the IP & subjecting it to possible post-filter contamination. FSO comes out of a nipple that contains a fine SS screen & valve that if junk got past the fuel filter, valve could clog. My guess is that the screen won't be your trouble (an opinion that is worth twice its price), as I'd expect to see run-time drivability w/the screen. Also, if you feel the FSO kick open when the key is turned on, I'd say it is working to allow a start and not the problem; if no tactile click-on, then it's toast & needs to be replaced.
3) I like the idea of a 65 degree garage. Year round if I could get it.

[JohnC]

On a '94 the lift pump will only run if either there is oil pressure present or the starter motor is energized. The circuits are largely separate for the two conditions, so it may make sense to confirm the lift pump runs when the starter is engaged. You may be able to do this simply by turning the key to start with the engine stopped and the gear shift in Drive. (Works on my '95) If it is not running it could cause exactly the symptoms you are describing.