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Engine Specific Info and Questions => IDI Engine => Topic started by: stopping on July 01, 2009, 05:07:24 pm
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The engine starts fine cold in the morning. Dos not start at all after being run for 30sec - 30min.
The timing is good.... cam very accurate, pump at .039" checked and double checked.... different pumps tried, different injectors (both: same results as the previous ones), the engine has been run from a jerry can so no restrictions, the solenoid plunger has been pulled, good glow plugs, seeming good cranking speed, the engine is really new... about one hour of idling total. Deck height is .62mm (max) and using a one notch gasket. Cranking speed is good but engine is tight and the starter is working hard.
The engine sounds great and it seems to have power particularly in the low end. Smokes a bit when gunned (blue-white) I have driven it around the block a couple times... I have bled the coolant system according to the Vanagan voodoo standard. What else......?
I would like to know why it does not start warm. I should say the last engine did the same thing.... when driven hard it would be difficult to start imediatly afterwords but this is bad.... it will not start at all. The head and the coolant set-up or the same since rebuilding the bottom end.
I am trying to be patient any advice welcome.
Stv
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Starter or grounds to the starter/engine. Start there. Or a weak or junk battery. I thought my flat red rabbit starter was fine, but after rebuilding it 2 times I got a reman from advanced the 3rd time...world of difference.
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Thanks 53...
Can anyone explain why it would be more difficult to start warm than cold?
Stv
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With my car cold starts are faster because the GPs get hot, when the engine is up to temp the GPs won't come on and since my timing is a bit retarded it cranks a bit. Pulling the cold start knob fixes that.
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Thanks 53...
Can anyone explain why it would be more difficult to start warm than cold?
Stv
If it's getting fuel and it turns over ok I'm betting it might be valve related, maby the adjustment is on the tight side and when warm it keeps them off the seat enough to not seal. This is a 1.9 though isn't it? Didn't they all have hydraulic lifters though? I don't know if a hydraulic lifter could cause that or not, it would turn over faster than normal though I'd think if not sealing right too. Possibly the valve guide clearance a little tight not letting it close. When you say the other engine did this too is it a completely different engine or does this engine have the other ones head on this engine? If so the problem is probably in the valves not sealing for some reason. Possibly a machine shop problem when grinding the valves sinking them deeper in the seats and not trimming the stem for the right clearance but at this point we have no idea what or if anything was done to the engine or head. If you are sure you have fuel and compression and timed close it should run and if not one of the 3 isn't there at the time. Tell us more about the head and if it was rebuilt when building this engine. How long does it have to sit before it will start again?
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Oh yes it is a AAZ 1.9TD in a Vanagon. I guess I need to re-do my signature. The head I have had for three years now.... I took it to a machine shop where they "tested" it and resurfaced it slightly. I don't what testing it involves but I would think it valve clearance/ holding pressure is part of it. They said the head was good.
The engine is a whole other block that I had machined for new 79.98 Kolbenschmidt pistons, new bearings main and rods, new rod/pin bushings, seals, I had the crank machined for the TDI "D" gear.
It does have hydraulic lifters yes the head is suspect because it is from the last engine..... I had to buy lifters for it when I bought the head... could they be the wrong size?
I have to leave the engine to cool for about an hour before it will start again.
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Maybe the cylinder pressure is higher when warm? Or the weak battery/bad cables/starter doesn't like a quicker burn in the cylinder? Those are my guesses to why it would start harder warm.
Also, see if your glowplugs come on when it is warm. That would do the same thing as above B/C the fuel would light way before it was supposed to and act like an over advanced condition...but it should slow cranking a little too...
My money is on the Battery connection to starter or starter itself.
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It sure sounds like valves not sealing to me from what you have said so far and about a half hour is about right for them to cool down enough to shrink a few thousandths to get back to seating. Pressure testing is a method the machine shop uses to test the coolant passages in the head to see if it will let compression escape into them, that's what happens when they refer to a head being cracked. I'm positive so far it's valve related from either wrong type lifters or something in that line but the bottom line is when the valves get hot they lengthen which is normal and that's why having enough valve clearance is important. Not enough clearance and it forces the valve off the seat enough to let compression leak off. When it's running it's probably still leaking a little bit but the piston is compressing the air so fast it isn't as noticible and doesn't have enough time to leak off enough for you to notice. But stop it and it will not build enough compression till the clearance gets a little bigger or actualy {some clearance period} which sounds like the problem from what I read so far. A compression test would show it but the time it takes to pull the lines and injectors and hook up the gauge the clearance will probably be back by then and not show up on the test. I think the 1.9 guys here would know more about the lifters but the valve clearance or lack of some sounds like what's wrong to me, .001 off the seat will cause it to not seal.
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With the engine hot, do a voltage drop test on the starting circuit.
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Lets get this clear. When you say it wont start are you saying it won't crank at all or spin fast enough or just not fire and cranking fine. If it won't even crank at all it's probably electrical, if it cranks fine and has fuel it's probably compression {valves off their seat} if it cranks slow it could be anything from a heat soaked starter which I doubt for just a minuet or so to cables, still doubt because the same problem would probably be there when it's cold too. You did say you had the engine bored, if it's cranking slow it's probably just that the engine is tight yet but will eventualy loosen up after you get some miles on it. But won't start is a broad description if we're not seeing or hearing it happening. If you have a good temp gauge and your oil pressure is good I'd drive it around and put some miles on it and see if it changes a little. My 350 in my truck did the same thing after it was bored, after it got a little warm ad you stopped it the engine had tocool down for a little to be able to spinn fast enough to start but it loosened up pretty quick. We only are supposed to have .001 clearance on these engines between piston and cyl when bored, that's pretty snug and if it's a little less it;s almost guaranteed to slow it down to the no start or even no crank point until it cools down and break in some and if the starter is a little weak or battey too the problems are more compounded.
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Mabe just not enough battery for the tight engine .... yes it is tight a thou would be about right. I have another set of batteries that are paired. Should I resolve to have two batteries? Right now the battery is just behind the firewall in the Vanagon and a shorter/fatter wire length than original but the battery is only 600CCamps.
I will be doing a compression test tomorrow.
It cranks.... fast cranking helps.. say when a friend offers me a boost from another diesel ... it did start sooner that the prerequisite 1/2hour. I will do a voltage drop test(good idea). The starter gets hot but I have not pushed it since I burnt it out once completely this week and once by half (one of the two ground brushes un-soldered itself. I turn the com and re-soldered with silver, put grease on the bushings and spray moly on the bedix and all seems to crank well now....just maybe not fast enough.
I am interested in this valve problem.... are there different size hyraulic lifters for these AAZ heads?
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There was a significant voltage drop on the battery when starting cold (down to 9v) I think that is a problem. It measured 12.75v before starting and 10.5 after starting... and yes it did start! More voltage reports soon.
I would like to assume for now that this might be a multi faceted problem......
There are two different types of lifters for that year of engine. What is the difference and what problems could result if I have the wrong ones?
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Ok here are the results,
The voltage drop when cold was not 9v it was 9.8v lets call it 10v. When cranking the hot engine, voltage drop is just under 11 volts and it does not start.
What is wrong?
There are two different diameters of lifters for this kind of engine....
26mm thick o/d 36mm 93 and less
26mm thick o/d 35mm 94 and later
Mine are 34.9 (35mm) there is no difference in thickness.... I don't think I have the wrong diameter of lifters since the tolerance is what I would expect...0.05 of oil around the lifters.
Maybe the springs are shot? But again this head is relatively new.
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I think it is the pump. The pump gets warm and it can't develop the pressure to open the injectors when it is hot. Same thing with the other pump... just so happens I have two tired pumps here (not that surprising).
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pour cold water on the head of the pump when it's hot and see if it will start then.
You should do a voltage drop test on the cables as well with the engine hot
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I think it is the pump. The pump gets warm and it can't develop the pressure to open the injectors when it is hot. Same thing with the other pump... just so happens I have two tired pumps here (not that surprising).
If you suspect a tired/worn injection pump, an easy test is to cool the injection pump off when it's hot and see if it starts. I'd cool it in stages so as not to "shock" the pump. I'd have 6 pots of water at 6 different temperatures ready: 160F, 140F, 120F, 100F, 80F,60F. Pour one pot at a time on the pump starting with the hottest,and see if it starts.
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Hello and thanks for the suggestions.
I did cool the IP with cool water and it seemed to make a difference. I will do a more extreme (hotter from running longer) test soon.
So if it is worn can I increase the internal pressure will that solve the starting problem? And how does a pump that worn affect the engine... damage from improper advance for example.
I guess it would be good to rebuild it.
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cooling the pump head with water made little difference. I would like to say it did but I got the engine hot by driving it for 20min, tried to start it, nothing; cooled with water constantly running over the head with a garden hose.....periodic starts. It took about 20min but it did start.... I guess that is better than it was before.
Is it still a bad pump?
Again there is good cranking... the fuel solenoid plunger has been pulled to eliminate that potential problem... so there is fuel, fast cranking, glow plugs and compression? It's got to be good. But I will see when I get the tester later today.
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A hot engine should start as soon as you crank the starter if everything is in order. You need good compression, properly timed engine and fuel for it to run. You said compression is good, engine is timed. Do you have air in the lines after you shut off the hot engine and not getting fuel? Have you tried cracking the nut at the injectors and verified fuel is spitting out of there while cranking the hot engine?
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whenever I see a warm engine not starting, I think of this thread...
http://forums.vwvortex.com/zerothread?id=3054819
i just recently learned the importance of very good grounds on my diesel ;D
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Compression is good.... well.... getting good, 380 was the lowest.
It must be the pump. I will have it rebuilt starting tomorrow.
Thanks for your help everyone.
Stv
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Compression is good.... well.... getting good, 380 was the lowest.
It must be the pump. I will have it rebuilt starting tomorrow.
Thanks for your help everyone.
Stv
The problem with getting the pump rebuilt it seems so many people on here have it done and it comes back not what they expected it to be unless it is from someone like Giles. This could add to your diagnosing the problem some more which you don't need. I doubt seriously you have 2 bad pumps. Just out of curiosity are both the fuel solenoids bad on the pumps? Your compression nummbers {cold I presume} seem to be alright if 380 is the lowest, what is the highest. If you want to possibly eliminate fuel or confirm it as a problem why not try shooting a spray of wd-40 in the intake and see if it tries to fire or run for a little from it? I've done it on my T/D to confirm I wasn't getting enough fuel and the motor fired right up on it and ran for a few seconds. I shot mine right into the turbo, about a 2 second blast, don't over do it because there is no throttle control doing this and you don't want the engine to rev up to high for too long. Don't use starting fluid for this test though, it's too volattile on a hot engine and has no lubrication at all. The WD-40 is a lot safer if it's a spray, not a stream. I've even used brake-kleen just to see if it would fire before diagnosing these kinds of problems. Just don't keep feeding it something like that to keep it running if it doesn't have oil of some type in it but it has to be in a spray form not liquid as it will cause serious problems because it doesn't compress at all. This kind of stuff is not for someone who doesn't have a good bit of experience and able to use the right judgement though and I don't know if you've ever done these kinds of things before. If not then I guess I better say don't try it. But if it would fire off the spray then you have a fuel flow problem, if it doesn't then you're back to compression again. You say it spins over fine so that pretty much would eliminate the electrical system period and you don't have the plunger in the solenoid so that eliminates it as a problem also. It starts and runs cold so that pretty much eliminates timing as an issue also. I'd hate to see you spend a bundle rebuilding a pump that might be fine the way it is and come back not as good as when it left and you still won't know the real cause and have a new problem as well. Me, I'd do the WD-40 test but if you've never done this stuff before especialy on a diesel get somebody who has done these type of things or don't try it. Obviously it's either fuel or compression related because it starts and runs when cool and cranks good when warm and until you can eliminate fuel itself it's still just guesswork. If the valves are to tight, just because you have 380 when cold it doesn't mean it's still there when they stretch a little when hot. I don't know what all your compression numbers were either but both my 1.6's after being bored had 450-475 right off the bat and climbed to 500 when they broke in so until you can eliminate fuel as the cause I still say your valves are leaking for whatever reason.
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I used propane to get it started when warm..... good stuff! No problem with over fueling either. This is a hydraulic head.
The compression numbers were at the lowest 380 at the highest... 460 with a couple of 430's in between.
Yes those numbers are cold.
I will be trying the other pump and putting it through the paces in the morning before I decide on a rebuild. There is a decent place here.. came recommended called Lew Diesel. http://www.canpages.ca/page/QC/pointe-claire/lew-dieselec-inc/4926956.html
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have you done the voltage test or ran new positive/negative cables? It is easier and cheaper than a new pump and won't hurt if they aren't the problem to have new. Same with the starter. I would have them tested before sinking the money for a new pump and it still might not work.
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You said engine is tight. Have you tried turning the engine by hand at the crankshaft bolt both cold and hot? Did it feel much tighter when hot? Have you checked the fuel tank vent and is there tank vacuum? You only gave cold compression numbers. What are the hot numbers?
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Thanks for responding.
I put my old pump on along with the IP pressure tester I have and it starts hot.... it wanted to start on one injector! when I tightened the second injector it ran quite smooth considering.
The starter, battery, wires, glow plugs, tank/ fuel restriction have all been eliminated as factors. Good for me cause they are better than ever now. really good cranking speed now despite the new engine.
I have not tried the hot cold turn it by hand trick that is a good one.. I will and get back to you.
I did not test the engine hot since caveman did not have enough time to wait for me to change it to my old pump.
Good news this morning. The old pump is behaving different than the "new" one. It starts the van when hot! So I miss read the starter/ battery... all that and those problems with bad pump. The pump might be bad but it is for other reason than warm start... I would say it is good... I need to fix a leak in the cold start (from worn aluminum not bad o rings) The internal pressure was too high (not set by me) and may have contributed to head gasket failure do to dynamic advance advancing too much. I removed the pump regulator and set it to 40psi/1000rpm. Sounds a bit more relaxed now.
I will have the other pump rebuilt by the masters in Newfoundland.
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It's okay Steve , you can tell everyone it was my fault for " selling " you a bad pump. ::)
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I'm glad to hear that you got it narrowed down to a fuel problem, at least you know now what kind of Gremlins to look for. I haven't tried propane yet, what do you do, just use a small propane torch and let it shoot in the intake? I hope your pump comes back good but I think you'll get it straightened out pretty quick now ;)
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Glad you got it running. I was going to suggest push starting it when it's hot just to see what happens, but I suppose that's not so easy in a van.
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Just a note:
40psi at 1000rpm is too low for IP pressure. I had the wrong number. I have set the pressure to 75 at 1000rpm.
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Just a note:
40psi at 1000rpm is too low for IP pressure. I had the wrong number. I have set the pressure to 75 at 1000rpm.
Can you go over how you set the pressure? Some pics would be great.
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Sorry i am really lazy and didn't read every post.
I had a "no hot start" dilema and the issue was slightly fixed by running my glow plugs on a relay&switch but the real issue was that there was no compression what so ever. My head had huge cracks in it and likely lots of other problems.
The coolant T at the head has a temp sensor that, when hot, tells the glow plug relay not to cycle and therefore you dont have glow plugs but that being said shouldn't it start fine then if those are normal parameters?
I would do a compression test. And if it comes out super low i'd take the head off and check it thoughrally. Possibly change the rings too while you're there. Rod Bearings and rings are a very easy job if you MARK EVERYTHING so they don't get mixed up and already have the head off.
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you need some free CLEAN table space too which is normally ;) hard to come by in our garages