Hard cold start - possibly down on power - help!

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fen
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Re: Hard cold start - possibly down on power - help!

Post by fen »

So if I did have a leak and the pressure wasn’t holding I’d see the fuel drain back to the tank, but if the fuel is holding after I shut it off it’s probably okay?

I removed the vacuum and reattached the fuel lines to the filter. I then had it running and cracked the bleeder on the filter. This caused massive air and the truck almost stalled. With it off I cracked the bleeder and then I had to pump a lot to prime the lines from the tank to the filter. If I left it for a few seconds the fuel would drain back to the tank. I primed it then started the engine and cleared the air and it held. So I’m guessing if I had an air leak or pressure issue the fuel would drain back to the tank like I saw but since it’s holding I’m probably okay.

I think I’ll move on to looking at the timing and trying a valve adjustment next.
'81 P’up 2.2L diesel dlx 5-speed 2wd short bed
‘93 Chevy G20 6.5L Diesel
'82 diesel Chevette (Isuzu 1.8L 4FB1) 4 door 5-speed
'99 Isuzu VehiCROSS 3.5L
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fen
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Re: Hard cold start - possibly down on power - help!

Post by fen »

Paul I read through your post about air leaks here.

viewtopic.php?p=44857#p44857

This does describe my issue where it’s harder to start the longer it sits.
Problem here is that with the fuel level low in the body the pump cannot deliver fuel to the injectors and you will have a no start or at best a very rough start. Usually, air leaks are sort of slow and a restart in a few minutes or an hour or more will be OK. Overnight and longer is where you usually will have trouble to start.

Would I see loss of fuel in the intake or return lines after sitting if there was an air leak causing the body of the injector pump to run low on fuel? Could a fuel and/or air leak in the IP cause this?

I drove it pretty good last night, power is better after fixing CSD. So I did just repair two fuel leaks but after sitting over night I don’t see any indication of a fuel leak at the pump or an air leak in the clear lines.

Is it safe to rule this out or could there be an issue with the pump?

Fuel lines after sitting over night
Fuel lines after sitting over night
Fuel lines after sitting over night
Fuel lines after sitting over night
'81 P’up 2.2L diesel dlx 5-speed 2wd short bed
‘93 Chevy G20 6.5L Diesel
'82 diesel Chevette (Isuzu 1.8L 4FB1) 4 door 5-speed
'99 Isuzu VehiCROSS 3.5L
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fen
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Re: Hard cold start - possibly down on power - help!

Post by fen »

I rechecked my video from the vacuum test. After shutting off the engine it looks like the gauge didn’t go to 0 but maybe to 1 or .5. Here’s a screen shot. I guess it was soo close I didn’t notice, but after reading your description it sounds like this is expected.

I guessing just need to leave it on like that for a while after shutting down to see if it holds just above zero



Gauge just above zero after shutting off
Gauge just above zero after shutting off
'81 P’up 2.2L diesel dlx 5-speed 2wd short bed
‘93 Chevy G20 6.5L Diesel
'82 diesel Chevette (Isuzu 1.8L 4FB1) 4 door 5-speed
'99 Isuzu VehiCROSS 3.5L
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fen
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Re: Hard cold start - possibly down on power - help!

Post by fen »

Okay I removed the top timing cover and used a 36mm on the crankshaft to rotate the engine. The timing marks look right at the timing mark on the pulley? Am I correct the first mark is the timing mark and the second mark is TDC? Anything else for timing to check?
Cam and injection timing pulley
Cam and injection timing pulley
timing and TDC mark chalked
timing and TDC mark chalked
Last edited by fen on Thu Apr 11, 2024 1:11 pm, edited 1 time in total.
'81 P’up 2.2L diesel dlx 5-speed 2wd short bed
‘93 Chevy G20 6.5L Diesel
'82 diesel Chevette (Isuzu 1.8L 4FB1) 4 door 5-speed
'99 Isuzu VehiCROSS 3.5L
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puttputtinpup
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Re: Hard cold start - possibly down on power - help!

Post by puttputtinpup »

Get a mirror andlook inside the crank pulley to see if the pulley alignment pin is as close to TDC as possible as shown in this picture. There are several timing marks on the pulley. Im still digging to see which mark for sure is TDC. I see another one in your photo farther down the rt side.
Screenshot_20240411-140443_Chrome.jpg
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fen
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Re: Hard cold start - possibly down on power - help!

Post by fen »

I stuck my camera and flashlight in there, it looks right.
Here’s what the manual shows, so maybe the first mark is TDC and then the other is this 45-60 BTDC mark? Or the 15 degree one?
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'81 P’up 2.2L diesel dlx 5-speed 2wd short bed
‘93 Chevy G20 6.5L Diesel
'82 diesel Chevette (Isuzu 1.8L 4FB1) 4 door 5-speed
'99 Isuzu VehiCROSS 3.5L
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puttputtinpup
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Re: Hard cold start - possibly down on power - help!

Post by puttputtinpup »

Another picture of pulley timing marks. Credit to arrowmntdiesel.
IMG_1894.jpg
The one the pointer is at. Verify with dowel pin at TDC
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fen
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Re: Hard cold start - possibly down on power - help!

Post by fen »

Yeah that looks like what I have set. So I think the pulleys are properly signed.

Also on the static timing I can only see this little mark no other. I guess to get that right I’ll have to try and get my hands on the special timing gauge J-29763…

So next up I’ll try and tackle the valves

This pic is looking at the IP just above the CSD
Possible injection pump alignment mark?
Possible injection pump alignment mark?
'81 P’up 2.2L diesel dlx 5-speed 2wd short bed
‘93 Chevy G20 6.5L Diesel
'82 diesel Chevette (Isuzu 1.8L 4FB1) 4 door 5-speed
'99 Isuzu VehiCROSS 3.5L
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puttputtinpup
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Re: Hard cold start - possibly down on power - help!

Post by puttputtinpup »

Looks correct. I'm not sure what direction you should take at this point. Mind boggling. Every diesel pup & luv I ever had fired right off when the glow plugs were working right.
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fen
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Re: Hard cold start - possibly down on power - help!

Post by fen »

puttputtinpup wrote: Thu Apr 11, 2024 4:34 pm Looks correct. I'm not sure what direction you should take at this point. Mind boggling. Every diesel pup & luv I ever had fired right off when the glow plugs were working right.
Yeah, hoping to figure something out. I imagine it could only be a few things left:

1. static timing / IP alignment (It's been fully retarded, fully advanced, and somewhere in between now).
2. Fuel not reaching nozzles -- I could crack an injector before cold start and see if it immediately sprays fuel when I crank?
3. Valve Adjustment
4. Low compression (damage from starting fluid use?)
5. Injectors spray pattern / pop off pressure



Adjusting valves now, is this right for intake and exhaust?
Labeled to match order from shop manual?
Labeled to match order from shop manual?

Shop manual
Shop manual
'81 P’up 2.2L diesel dlx 5-speed 2wd short bed
‘93 Chevy G20 6.5L Diesel
'82 diesel Chevette (Isuzu 1.8L 4FB1) 4 door 5-speed
'99 Isuzu VehiCROSS 3.5L
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Paul
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Re: Hard cold start - possibly down on power - help!

Post by Paul »

I watched your cold start video on you tube and noted the way you were using the glow system. You were running a couple of cycles of hi glow but not cranking and then running the glow by leaving the clutch out and then cranking. If I have this right, it is not a good way to use the glow system. When leaving the clutch out and turning to crank, the system glows through a dropping resistor which will reduce the glow current and the glow plug temperature greatly. Not sure just how much, probably to less than half of high glow.

The best way to use the glow system is to wait about two or three seconds after the glow lamp has gone out and then crank, but before you hear the relay turn off.

If this doesn't improve your starting I think you should troubleshoot the glow system. Start by measuring the glow current with a clamp on current meter. The current should start at about 140 amps and then decline to about 40 amps over about 7 seconds after which the glow controller will shut the current off.

Paul
'84 P'UP 2 wd diesel, 5 spd with 0.78 fifth gear and differential back to 3.73.
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fen
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Re: Hard cold start - possibly down on power - help!

Post by fen »

So I did the valve adjustment. A lot of them were fairly loose. Tightened down to .016" until the feeler had decent resistance but hopefully not too tight. The manual mentioned check the rocker arm shaft bracket bolts for looseness, I'm not even sure what bolts those are but I think the 8 bolts on the rockers? Anyhow none were loose so I left it alone.

While I was doing the adjustment I believe I noticed some coolant leaking / dripping. Not sure why or where. Perhaps from bumping all of the hoses?

Started up the truck, it was 7pm and 60's out and truck had been sitting since the previous evening.
Was still a hard start but perhaps slightly better. I again noticed air bubbles from the filter to IP after starting, but the lines are all holding fuel when it's off.

I tried the vacuum test again. Not sure about my little harbor freight gauge, maybe I'll get another one. But the gauge has some pressure when idling and then drops to just above 0 after shutting off. It held at just above 0 overnight.

Could a bad injector or something be causing this?
Is there something I could test with cracking the injectors? E.g. if the injector is spraying fuel right away on cold start?
Now that I have the valves adjusted I'll try getting a compression tester too.

I made some videos of the valve adjustment and starting it after along with a look at the air bubbles:

Valve adjustment:
https://www.youtube.com/watch?v=zbZ_JUm5xWE

Starting after valve adjustment and noting air in lines again:
https://www.youtube.com/watch?v=Vj4pcxphQws
'81 P’up 2.2L diesel dlx 5-speed 2wd short bed
‘93 Chevy G20 6.5L Diesel
'82 diesel Chevette (Isuzu 1.8L 4FB1) 4 door 5-speed
'99 Isuzu VehiCROSS 3.5L
User avatar
fen
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Re: Hard cold start - possibly down on power - help!

Post by fen »

Paul wrote: Thu Apr 11, 2024 10:58 pm I watched your cold start video on you tube and noted the way you were using the glow system. You were running a couple of cycles of hi glow but not cranking and then running the glow by leaving the clutch out and then cranking. If I have this right, it is not a good way to use the glow system. When leaving the clutch out and turning to crank, the system glows through a dropping resistor which will reduce the glow current and the glow plug temperature greatly. Not sure just how much, probably to less than half of high glow.

The best way to use the glow system is to wait about two or three seconds after the glow lamp has gone out and then crank, but before you hear the relay turn off.

If this doesn't improve your starting I think you should troubleshoot the glow system. Start by measuring the glow current with a clamp on current meter. The current should start at about 140 amps and then decline to about 40 amps over about 7 seconds after which the glow controller will shut the current off.

Paul
Update: I had a really hard start this morning. Just could not get it to go. I still had my vacuum gauge setup so I disconnected it and reconnected lines to filter. I felt like at one point there was a loud knocking sound when trying to start up. I was getting scared I wouldn't get it to go or the valve adjustment went wrong.

Also when I removed the vacuum gauge and reconnected to the filter the fuel was rushing back to the tank. Tried priming it with the hand pump. Fuel would suck back up from the tank.

I finally got it to start, I cycled the qlow plugs twice, then held the key to start with the clutch out a lot longer, maybe 15 seconds. Cranked and finally started firing better.

Paul I wonder if there is an issue with my glow plugs then or if holding the key to start is just letting it warm up the block enough to get started...

Next cold start I'll try holding the key to start with the clutch out longer. If that way is working better maybe the qos is heating the plugs but not enough?

I'll see if I can try a current / voltage test to see.
'81 P’up 2.2L diesel dlx 5-speed 2wd short bed
‘93 Chevy G20 6.5L Diesel
'82 diesel Chevette (Isuzu 1.8L 4FB1) 4 door 5-speed
'99 Isuzu VehiCROSS 3.5L
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Paul
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Re: Hard cold start - possibly down on power - help!

Post by Paul »

fen - -

Seems like you are still not glowing the best way. Here is my recommendation again:

"The best way to use the glow system is to wait about two or three seconds after the glow lamp has gone out and then crank, but before you hear the relay turn off."

Paul
'84 P'UP 2 wd diesel, 5 spd with 0.78 fifth gear and differential back to 3.73.
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fen
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Re: Hard cold start - possibly down on power - help!

Post by fen »

Paul wrote: Fri Apr 12, 2024 11:44 am "The best way to use the glow system is to wait about two or three seconds after the glow lamp has gone out and then crank, but before you hear the relay turn off."

Paul
Paul I was trying this but it just cranks without firing. Or it doesn’t get it started. The method I mentioned above is what finally got it going. Holding the key to start for longer.

I’ll try holding key to start with clutch out next cold start a lot longer and see if that helps or not. It’s weird sometimes it’s very hard to start and sometimes it starts kind of hard like after I did the valve adjustment. But that was in the evening when it was a little warmer out.

I do feel like I’m using the glow plugs to compensate for another issue though. The truck is hard to start off sitting for just an hour or two without using the glow plugs. I disconnected the thermo switch so the plugs always fire.
'81 P’up 2.2L diesel dlx 5-speed 2wd short bed
‘93 Chevy G20 6.5L Diesel
'82 diesel Chevette (Isuzu 1.8L 4FB1) 4 door 5-speed
'99 Isuzu VehiCROSS 3.5L
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