Unusual difficult start problem

[DeliTan]

At least I think its unusual but I hope to be proven wrong with the answer (help please).

'96 L400 LWB 4M40 119k kms. Vancouver area

Never really had a problem starting it but I'm usually in Mexico during the cold weather. I did buy some new glow plugs in 2010 or 2011 but they made things worse so I put the originals back in.

I wait for the second click, start it up, bring the revs up to 1500 and hold it there until the EGT is over 100˚F, then drive away while it stumbles for a few seconds, then all's good.

Lately (OK a few times) after driving for a few minutes, it feels like it is running out of fuel. My right foot works to keep it going but it ultimately stumbles to a stop. Then after more starter than I wish to apply, it starts and is fine for the rest of the day.
I have only seen this when it is cold (for Vancouver).
I'm guessing its a cold weather fuel supply problem but I bow to the more knowledgeable.

I plan on putting in a block heater but suspect that won't solve this problem as the fuel won't be heated.

Ideas?

john

[Mr. Flibble]

Fuel pump seal might be leaking and drawing air, making for a hard start.

Could add some canola oil to help, but the seals days might be numbered.

Could be fuel filter as well, but I would expect that would be constant.

[DeliTan]

Thanx Mr. Flibble, and those who responded by PM.

We will be replacing the offending seal(s) in the injection pump and replacing the fuel filter this Saturday.

If time permits, we'll replace the engine oil and filter and install a block heater as well. (and maybe troubleshoot the AC)

After extensive research, here and elsewhere, I found there are 2 places, and sizes of frost plug heaters. I'll detail the options after I've installed mine.

john

[mistral]

Very interested to hear the outcome of the work on your IP and other bits. I had a similar cold weather start problem, same struggle and death throes. After some poking around I suspected glow plugs and checked...only 1 plug was drawing spec current (!) with all others well under. Causes: excessively long cable from the glow relay to busbar; steel busbar (one of the worst metals for a busbar...poor conductivity !!) so I made a new one out of aluminium; bolted the power feed to the dead CENTRE of new bar to distribute current more evenly across all plugs. Absolutely sorted out my problem.The correctly clicking relay sequence means the timing circuit is working but doesn't necessarily mean adequate power is getting to all your plugs.

[DeliTan]

The title I picked for this thread is inappropriate as the problem I was having is common, just not to me.

My friend Alphonse, the experienced mechanic, and I (I tried to stay out of his way, but mostly failed) pulled the injection pump and replaced a seal (only one was needed). After watching this, I'm glad I didn't try to tackle it on my own. Even a dummy like me could probably pull the pump and replace that seal, but putting it back in with the timing set correctly then adjusting things, was way over my head. Experience rules! Because we were changing the fuel filter, we needed to pull the batteries anyway and the tray was in the ip's way. Three of the 5 bolts for the tray were rusted solid so it was a bit tough to get them out. Once the tray was out, it was far easier to get the ip out.

Although I don't expect to need a block heater in Vancouver, I wanted one anyway. Maybe I'll need it sometime... The plan to do this was started after I read Dino's excellent report. He installed a 50 mm frost plug heater in the hole near the ip, so I figured that would be the best time and place to do it. Following more research and reading from the block heater supplier's website, I decided to go with a 40 mm Temro (Zerostart) 3100049 frost plug heater and put it on the rearmost right side hole. Theoretically it will work better if installed lower. I don't plan to plug it in unless I experience prolonged sub zero temperatures.

Six hours after starting, we went for a test drive and all seemed good, so then we did an oil and filter change and checked everywhere for leaks.

Alphonse (not his real name) also checked my existing glow plugs, my spare glow plugs, my charging system, glow plug relay and probably lots of other stuff I wasn't aware of. He also warned me I will need a new crankshaft pulley one day.

I can't yet say if there is any change to the starting, as I haven't driven it from cold, since we finished yesterday, but knowing it's done feels good. I will comment again after I've lived with it for a bit...

john

[DeliTan]

So its been a while since I had that service done. Even though I haven't had a really cold day to test the starting, I want to complete this thread.

Things I now know:
My baby starts with less hesitation and complains (stumbles) less.
I don't have to wait as long as I did before (EGT = 100˚F) but I do anyway.
EGT temps at known hills under same driving conditions as before are lower. Presumably saving fuel.
Seems to require less foot pressure for same speeds.

Subjective:
Feels smoother (whatever that means)

Cold idle speed isn't as high as I would like, but that's a minor adjustment I will get to some day. In the meantime I still like to hold it at about 1500 rpm until the EGT gets to 100˚F. The drive away is flawless then...

john