Hard cold start - possibly down on power - help!

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

Post by fen »

Short version:

This week I brought my truck to an injection shop to having the timing checked /adjusted due to difficult cold starting that seemed to have started after a botched timing belt job a couple years ago. After botched timing belt was replaced by another mechanic the truck would start okay after cycling the glow plugs a couple times at ~40 degrees. Glow plugs seem to be working fine. Truck still had Good top end speed / power etc. I resigned to mainly driving it in the summer or above 60 degrees out. Once warm truck starts fine.
  • Shop said static timing was fully retarded, so they fully advanced it. They never pulled the cover or checked the pulley timing. Though they originally said they had the dial gauge and I thought they would set it that way, they DID NOT.
  • I went to pick it up and truck would NOT start. They set it back to fully retarded. Still wasn't starting like it did before I brought it to them. They advanced it a bit. Finally after a ton of cranking and pumping the pedal did I get it to start.
  • Tech was going to try starting fluid but I told him off.
  • I drove the truck home. Now with timing advanced a bit I seem to notice a ticking sound and I feel like truck is revving a higher / less power especially over 40 mph though I can get up to freeway speed.
  • Truck also is harder to start if I let it sit for a couple of hours after warming it up than it was before.
  • Shop also noted a leak from the CSD. I noticed it was wet with fuel around it too but didn't see any constant dripping.
what happened to my truck?

My thoughts:
1. Test compression - perhaps unruly use of ether to get it started blew the compression?
2. Buy a dial gauge and check timing is spot on. Isn't off a tooth or 180 degrees or what not as well.
3. Could fuel leak from CSD cause this? Though it doesn't seem like it and I doubt the fuel leak is the new issue. Shop tried to say it's air in lines or loss of prime of the IP?

What would happen if timing is off 180 degrees or off a tooth? Could that be why the IP static timing was fully retarded in the first place? I'm not convinced that's actually the factory setting.


video of ticking sound if you listen carefully.
https://www.youtube.com/shorts/Apq8I6RDJGY

____________________

Additional details:


Previously I had just fixed a leak in the injection pump at the full load adjustment by replacing the o-ring, this stopped fuel dripping but I don't think it helped my cold start problem (or hurt it).

Years ago when I had the timing belt replaced. Someone screwed it up -- I can't quite recall what happened if they slipped the timing or what. They couldn't get it right so they gave up. I had someone else look at it, I recall them adjusting the static timing and then they took the truck and got the belt changed. After that it started up but always seemed like it started harder. I also distinctly recall the truck sounded louder, but then quieted down as soon as I pulled off. This happened once at the shop once I finally got it started. After letting it idle for a while I did a quick test drive. As soon as I started going I noticed the same 'quieting down'.

My thought recently was to check the static timing, maybe when it got adjusted it bumped it off. After contemplating doing it myself I decided to drop it off at a local diesel injection shop here (master tech). Over the phone they said they had the timing dial and could "time anything".
Monday morning I started the truck up, (cycled the plugs twice), and fired right up.

I ended up calling them about the progress and went to pick it up today. Over the phone the tech said the timing at the factory timing which was retarded so they advanced it a bit though it was still hard to start. Okay I'll come get it. When I got there they gave me the keys and waived charging anything. I went to the truck and it would not start. I tried cycling and cranking a couple times. I went back and talked to them and had them set the static timing back. I guess they said it was fully retarded and they fully advanced it. The tech came over and set it all the way back. I still couldn't get it to start. They tried advancing a bit or maybe half way... finally I got it started after A LOT of cranking.

I was going to try setting the timing back to fully retarded but I don't have the right tools. It seems the nut on the IP flange is rounded and slipping on me with a box end wrench.

I'm a bit out of my realm on a lot of this now and thinking this might be the end of my pup :(
'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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JoeIsuzu
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Re: Hard cold start - possibly down on power - help!

Post by JoeIsuzu »

Tony,

Somehow I had not put 2 + 2 together. I didn't realize that's you on the Isuzu P'up Facebook group.

So this is partly in response to this post and posts on the Facebook group -- particularly this one:
https://www.facebook.com/reel/439761821864500
I don't put much stock into trying to diagnose and troubleshoot based on sound. Yes, the ticking sounds, but given the troubles you've had, I highly recommend getting all the way back to known good settings before trying to troubleshoot any further. That is, just to do a timing belt replacement, but using the same belt. The procedure is here, and has some good photos:
Timing Belt Replacement
This job requires no special tools, and if I can do it, anybody can. ;)

Until you've done that, there's no point in looking at the static timing.

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

Post by fen »

Thanks Jack, I think you’re right.

After driving it around and letting it sit I definitely noticed a csd leak. Which is also what the shop said. I don’t know if this just developed or not. It’s not much like my dripping full load screw I just fixed but it’s wet on the bottom and I see a diesel drip underneath when parked for a while. The csd is a bit of a mystery to me but this thread did seem that it could cause these problems?

viewtopic.php?t=7773
There is a problem with it though which causes the normal (running, not start up) timing advance to fail or partially fail or intermittently fail. This is very serious as the engine power and fuel economy are adversely affected when the the timing does not advance. Also, exhaust smoke will be much higher and the engine temperature will likely run higher, although this may not be noticed as these engines run unusually cool.
Would it make sense that it’s also causing a hard start after sitting a while that the IP is losing its prime?

My thought now is to fix this csd leak since it’s obvious.
'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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Re: Hard cold start - possibly down on power - help!

Post by JoeIsuzu »

fen wrote: Sat Mar 30, 2024 5:05 pmWould it make sense that it’s also causing a hard start after sitting a while that the IP is losing its prime?
I really don't know what effect a CSD leak would have on starting and on performance. But the thread you reference is probably the definitive source of info on the Isuzu CSD (thanks to Paul, Andy, and others).

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

Post by fen »

Here’s where it looks like it’s leaking from the csd.

Also noticed an air bubble entering my in line fuel filter every 30 seconds to a minute.
Attachments
Air bubbles
Air bubbles
Appears to be leaking fuel around here
Appears to be leaking fuel around here
'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 this is weird.

Before taking to the shop for the static timing I replaced the o ring in the full load adjustment screw because I had a good drip every couple of seconds from there. After picking it up from the shop I noticed the fuel around the CSD housing. I've been watching for fuel leaks any where and wiping them up so I can see. I started the truck early this morning and drove it around a couple of miles and parked it. Later I noticed a lot of fuel on the ground underneath.

I've started up the truck every couple hours and mostly just idled it looking for fuel leaks. I cleaned up fuel from the csd and the bottom IP bracket, which led me to start thinking I had a fuel leak from somewhere else on the pump. I noticed a bit of fuel around the shut off solenoid so I cleaned that up. I thought maybe that's what's leaking?

Tonight I started the truck up after sitting for about 3-4 hours and it took some extra cranking. Then I went to look for fuel leaks and THE FULL LOAD ADJUSTMENT WAS CONSTANT DRIPPING!

Okay what the heck, so I stopped the truck, backed off the nut a bit (this turned the screw slightly, then retightened the nut but just as the adjustment screw started to turn with it. I didn't turn the screw as much as it was before may 1/16 turn less... Then wiped up the fuel and started the truck up again. NO MORE LEAK!

Then I took the truck out for a drive around the block. I have to say it didn't sound as loud and when I started going I noticed I had more power. I was shifting later at 2nd and 3rd gear again. Awesome!

About a quarter mile in as I pulled out from a stop sign... same problem as before! Revving high to change gears and seemed like loss of power.

I got back home and looked for leaks while it was idling. None at the adjustment screw. Yes fuel around the CSD.

I'm now sure the CSD is the problem for my lack of power. But why did the full load adjustment start leaking again!? Maybe it's only leaking on cold start? Did I fix it? Is it going to leak again? Did I screw something up? Did this cause the CSD to start leaking?

Do I need to tighten that lock nut more? Maybe back the screw up just a bit and tighten it down until it's good n tight and back at the same spot?

I'm going to let it sit and do a cold start again. If it's leaking I'll try to just turn it off and back on without retightening the screw.
'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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Re: Hard cold start - possibly down on power - help!

Post by puttputtinpup »

Fen, I'd be careful about over tightening the nut risking stripping the threads. I don't believe the leaking screw is related to the CSD. Regarding performance, I'm kinda wondering if the CSD piston inside might be getting hung up and keeping the timing advanced (where it should be for cold starts) then finally moves and the timing is returned to "normal", which is already too retarded. I suggest sending a PM to 'Paul' on the forum and get bis input. I still think going back to the timing belt alignment check will be crucial in troubleshooting the cranking and performance issue.
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Re: Hard cold start - possibly down on power - help!

Post by fen »

CSD gasket kit on the way.
Ordered some clear fuel line mentioned in this thread:
viewtopic.php?t=18455
except I ordered 3/16 ID for the return lines. Hopefully that will help seeing if this is an issue with leaks etc.
Ordered a new timing belt and tensioner. If it does look off I may as well change it out.

Going to replace lines and CSD first. Then I'm going to check the timing and adjust valves (new gasket on the way too).
After that check compression.
'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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Re: Hard cold start - possibly down on power - help!

Post by fen »

Here's a video of my hard start after sitting for a week.

Currently working on putting in clear fuel lines.

https://www.youtube.com/watch?v=HoDlCaCq5Uw
'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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Re: Hard cold start - possibly down on power - help!

Post by puttputtinpup »

So with the door open (or turn on the dome light to see it's brightness) does it dim and stay dim while the glow plugs are heating? Or dim and get bright again quickly?
Have we double-checked the timing belt marks tonsee if they're all lined up correctly at top dead center? The keyway slot in the crank is TDC and should be a corresponding mark on the crank pulley.
When removing any of the timing belt covers, keep track of which bolt went where. Lengths specific to each hole. The longest can be use to screw through a hole in the inj pump sprocket to hold it still in the correct position. Just DON'T FORGET to REMOVE IT before rotating the engine to seat the belt.
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Re: Hard cold start - possibly down on power - help!

Post by fen »

Yes, the light dims a bit when the plugs are on and returns to normal when the relay clicks off. The bus bar gets hot. I think the glow plugs are all good and working. I cleaned up all the connections and new glows recently too. I haven't checked the actual voltage to the glow plugs when heating though.

Also I'm confident it's not the glow plugs. Here's why. If I get the truck warm and then let it sit for an hour or two and go to start it by just cranking right up (or connecting the thermo switch so the glow plugs don't come on) it will just crank but not start. If I instead cycle the glow plugs once and then crank, it starts right up. This also leads me to believe it's not an air leak either. When the truck was good it would likely start right up without the glow plugs in this case.

I have not checked the timing yet, I plan on getting to that after fixing the CSD fuel leak. That's a good note on the screw to lock it, thanks!

Here's a vid of the new clear lines installed. It took driving around a couple of miles for the return line to fill with fuel off the injector.

Any ideas what I should expect here? If everything is working and if there's a fuel leak at the CSD?

https://www.youtube.com/watch?v=5LDRc5TzaUM
'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 »

Update:

Here's a vid after I initially installed the clear return line from the injectors. It took a while for the line to fill with fuel and be purged of air. No idea if that's indicative of anything.

https://www.youtube.com/watch?v=BYk1SuXwHcw

I did rebuild the CSD. Did seem to help restore power but doesn't appear to have affected starting.

I also removed the inline filter I had but neither that or new lines seem to have made a difference in the hard start.

I let the truck sit for a few hours overnight and tried to start this morning at 40 degrees. Still hard starting, started on the second attempt.

Here's a video of that start and a shot of the clear lines:

https://www.youtube.com/watch?v=A-F7w4d1SUQ

Next I'll tear in and check the timing belt / pulleys. Then thinking to do a valve adjustment and then do a compression test. Stay tuned.
'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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Re: Hard cold start - possibly down on power - help!

Post by puttputtinpup »

In the past we've had members mention lots of smoke from the exhaust but after retarding the timing, it cleared up some. The truck at least starts when timing is retarded all the way. Just doesn't start well.
If the timing belt is off by a tooth or two and causes it to be too far advanced, getting the belt lined up right could make the difference.
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Re: Hard cold start - possibly down on power - help!

Post by fen »

I did yet another cold start video. I didn't see any air before / after starting but I did notice some air in the fuel line after the fuel filter once it warmed up.
https://www.youtube.com/watch?v=yrygSzORa_A

I tried T'ing in a vacuum gauge after the fuel filter. I got 2.5 in Hg while running but it went to 0 right on shutdown.
I tried bypassing the fuel filter but I got no reading on the gauge while it was running.

https://www.youtube.com/watch?v=uk8quhSbL1M


Quick vid on the amount of smoke idling after cold start:
https://www.youtube.com/watch?v=hMzzgZQl5j8
'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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Re: Hard cold start - possibly down on power - help!

Post by Paul »

fen wrote: Wed Apr 10, 2024 5:18 pm I did yet another cold start video. I didn't see any air before / after starting but I did notice some air in the fuel line after the fuel filter once it warmed up.
https://www.youtube.com/watch?v=yrygSzORa_A

I tried T'ing in a vacuum gauge after the fuel filter. I got 2.5 in Hg while running but it went to 0 right on shutdown.
I tried bypassing the fuel filter but I got no reading on the gauge while it was running. Quick vid on the amount of smoke idling after cold start:
https://www.youtube.com/watch?v=hMzzgZQl5j8

https://www.youtube.com/watch?v=uk8quhSbL1M

The 2.5 inches of mercury is about right for the lift from the tank. But, most of the negative pressure should hold when the engine is shut down. If it does not, you do have a leak somewhere in your fuel feed or fuel return lines. Either place will let air into the system and let the fuel drain back to the tank, including the fuel in the pump body. This will make the engine slow to start as the pump body will need to refill.

Paul
'84 P'UP 2 wd diesel, 5 spd with 0.78 fifth gear and differential back to 3.73.
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