Question about timing...

General Bellett, Gemini 75-98, Piazza 81-93, Bellel, Florian, 117 Coupe, Minx, Aska technical discussion.
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Post by impulsive » Sat Jun 02, 2012 1:06 am

Hey, I put the fuel lines back on the way they were originally. I will take a picture and post it later just to make sure, but to describe it, there is the hard line that comes up from under the car, it connects to the FPR on the back of the plenum chamber, and then from the other side of the FPR it goes to the feed nipple on the fuel injector rail. This is how it was originally.

Thanks - Bart
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Post by wedgenut » Sat Jun 02, 2012 5:37 am

Be careful that you identify your fuel lines correctly. There are two "hard pipe' the FPR is fitted on the return line. This is how it maintains fuel pressure in the injector rail. This is not just Piazza, it is standard method on all cars with EFI
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Post by impulsive » Sat Jun 02, 2012 6:20 am

Well, what confuses me, is it seems there are two FPRs. One before the rail and one after. Is that correct?

Here are photos of my car's engine bay before the tear down. You can see the FPRs I am referring to. One is an aftermarket Bosch. The other is stock.

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Post by wedgenut » Sat Jun 02, 2012 2:36 pm

The one on the supply line is NOT a pressure regulator. It is what is called a fuel damper, it prevents fuel pulsing but it does not reduce pressure. If you imagine the pump is supplying full pressure to the fuel rail and the FPR is working correctly to maintain the rail pressure everything is right...YES? Not necessarily, every time the injectors fire there is a momentary pressure drop and sudden pressure recovery. This is termed "RAIL PULSE" As injectors work best with smooth even pressure one way to minimise this pulsing is to fit a fuel damper. It is an accumulator if you like. The FPR is maintaining your rail pressure and the damper is reducing the rail pulse.

It is very unlikely this has any bearing on your hard starting problem. If the FPR on the other hand is not maintaining pressure in the rail it WILL be hard to start or will start and cut out.

You need to do the basic checks mentioned before and check your fuel pressure. Many of the things you are worrying about can be eliminated by basic inspection and testing. Do the checks, then you can tick them off one by one. You have a manual so follow the procedures set out in there and you will very quickly reduce the number of items that could be problematic, ultimately you will find the problem.

This is not complicated, if you have the engine correctly assembled and valve timing correct you should have good compression when the pistons rush up the tubes. If you give it fuel and air in the correct ratio when they arrive and a spark at the right time IT WILL START. If it doesn't then something isn't right or isn't happening at the right time. mechanical settings like valve timing CANNOT change once set. Ignition timing CANNOT change once set. So get those right and move on. Make sure you have constant fuel pressure at the correct level. If you have, move on. Make sure no birds are nesting in your AFM and air hose and that all hoses are in the correct place, tight, no leaks or cracks and that the IAC valve is working correctly (open when cold) and move on. Now all you have left is spark and injectors. It is simple step by step stuff, don't keep going back and forwards or poking at things in a random way.

Sorry if this comes across a bit blunt but you seem to be going in circles.
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Post by impulsive » Sat Jun 02, 2012 11:13 pm

wedgenut wrote:Sorry if this comes across a bit blunt but you seem to be going in circles.
LOL, I'm not going in circles, just not going at all! Right now I am not even at home. Part of my frustration has been my lack of time to work on it!!

Thanks for your help.

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Post by impulsive » Tue Jun 12, 2012 3:07 pm

I hooked up a pressure gauge tonight. I'm not sure if I did it right, but with power to the fuel pump, it looks like the pressure is hitting 50 psi. This is just with the gauge hooked up and nothing disconnected or unplugged like the manual calls for. Its hard to understand what it actually wants you to do. And the flow chart for no start tells you to check fuel pressure, then you go to the section that talks about checking the fuel pressure, and it talks about different scenarios and one of which is checking it at idle, which is pretty stupid, imo, since the car doesn't even start.

This project is no longer fun.

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Post by IPTOC » Wed Jun 13, 2012 1:00 am

Just to go back to a post from Wedgie on page 3 (or 4?), on the Turbo models, the plug which fits the knock sensor IS EXACTLY THE SAME as the one which goes to the Idle Air Control valve under the inlet manifold, and it is entirely possible to get them muddled up.
I'm not sure if this will cause your issue (I doubt it, the car should still fire up), but it certainly needs to be added to the checklist so that you can ensure as many things are correct as possible.
I usually check fuel supply by first disconnecting the main fuel IN pipe from the fuel damper that is sited at the rear of the plenum chamber and keying on - a fooking great jet of fuel should shoot across the engine bay.
If in your case it doesn't, then it sounds like a classic case of 1988MY onwards in-tank fuel pump failure to me.
Also, to hark back to a previous post about fault codes, the ECU will only register fault codes if the engine has been RUNNING when a fault has developed.
Another point is that yes, the ITEC injection system IS batch fire, i.e. all of the injectors fire at once, twice for every crank rotation. The ECU knows the crank position (and therefore when to fire the injectors) by way of the crank angle sensor, which is actually housed in the DISTRIBUTOR. If the distributor is faulty (I've seen a few), it will still show a nice, fat spark at the plugs, but the ECU won't be able to tell what the crank phase is, and therefore the injectors (if they fire at all) will be all over the place.
Having said that, the distributors are an absolute PAIN to get lined up correctly on these - one "tooth" out in either direction and the damned thing won't fire at all, regardless. Try carefully pulling the dizzy out and moving it ONE "tooth" to the left, try starting. If that doesn't work, move it back TWO teeth to the right (so you're effectively one tooth right of where you started) and try again.
Last edited by IPTOC on Wed Jun 13, 2012 6:59 am, edited 1 time in total.
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Post by IPTOC » Wed Jun 13, 2012 6:58 am

Me again!

Curiosity got the better of me in terms of your quest to find the diagnostic links and I dug out the 88/89MY Impulse workshop manual when I got home.

Similar to the RHD Piazzas, the Impulses have diagnostic links sprouting from the harness close to where the multiplugs are for the ECU (under the dash on the driver's side).

You are looking firstly for the ALDL (auto diagnostic link lead) plug which is a three pin, black plug (pins in a "Stonehenge" type arrangement looking in the end of the plug), fed by a Black/Red wire, a Yellow wire and a Black/Yellow wire (terminating at ECU pins 44, 21 and 51 respectively, should you wish to know). This is used at the factory and by dealers who have the (now ancient) kit to plug into it.

Very near where this plug breaks out of the main wiring harness should be two seperate wires - one Blacl/Red, terminating in a shrouded female spade terminal, the other Black/Yellow and terminating in a male spade terminal. They may be looped up and secured to the harness outer with a cable tie.

THESE ARE YOUR SELF-DIAGNOSIS WIRES. With the ignition off, plug the spades together. Switching on the ignition will then cause the CHECK ENGINE light to start flashing. It will first cycle the number 12 three times in the following format:

ONE FLASH - short pause - TWO FLASHES - long pause - ONE FLASH - short pause - TWO FLASHES - long pause - ONE FLASH - short pause - TWO FLASHES - long pause

12 is the code for A-OK and, if there are no further codes stored, it will continue to cycle 12 in this fashion until you turn off the ignition and seperate the diagnostic wires.

If further codes are stored, they will be displayed three times in the same way, for example code 66 for a knock sensor problem: SIX FLASHES - short pause - SIX FLASHES - long pause - SIX FLASHES - short pause - SIX FLASHES - long pause - SIX FLASHES - short pause - SIX FLASHES - long pause.

Once all the codes have been displayed in sets of three, the code 12 will be displayed three times again, and the cycle will repeat itself until you turn off the ignition.

Hope this helps. By the way for anyone with a Piazza reading this, your ALDL plug has the same configuration and wire colours, but is WHITE in colour.

Best regards from raining England!!!
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1988 Isuzu Piazza HBL Manual - Romanesque Silver
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Post by impulsive » Wed Jun 13, 2012 7:19 am

IPTOC wrote:Just to go back to a post from Wedgie on page 3 (or 4?), on the Turbo models, the plug which fits the knock sensor IS EXACTLY THE SAME as the one which goes to the Idle Air Control valve under the inlet manifold, and it is entirely possible to get them muddled up.
Yup, I've tried switching those two already. No change.
IPTOC wrote:I usually check fuel supply by first disconnecting the main fuel IN pipe from the fuel damper that is sited at the rear of the plenum chamber and keying on - a fooking great jet of fuel should shoot across the engine bay.
Yup, got loads a pressure hitting the rail. I can 'T' in a fuel pressure gauge there, and it reads about 50psi while keying on. So I know its getting juice. I have not pulled the injector rail yet to see if they are actually squirting good, but for now I think they are.
IPTOC wrote:the distributors are an absolute PAIN to get lined up correctly on these - one "tooth" out in either direction and the damned thing won't fire at all, regardless. Try carefully pulling the dizzy out and moving it ONE "tooth" to the left, try starting. If that doesn't work, move it back TWO teeth to the right (so you're effectively one tooth right of where you started) and try again.
I guess I will try that again. I feel like I've done that 100 times now. :)
IPTOC wrote:Similar to the RHD Piazzas, the Impulses have diagnostic links sprouting from the harness close to where the multiplugs are for the ECU (under the dash on the driver's side).
Yes, I should have mentioned this, but I did finally find the leads. They were so far jammed up there it took me a while. So far, my codes are clear. I need to get the damn thing to fire up and see what I get. I leave the neg lead off the battery when I am not troubleshooting, so until I get it to start, I won't be able to pull any numbers other than 12.

The symptoms I have still seem like timing, but again, I can't see how that could be. I'll keep working at it either way.

Thanks- Bart
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Post by IPTOC » Wed Jun 13, 2012 8:06 am

Hi,

Certainly sounds like you've tried pretty much everything.

Your spark plugs will be wet if the injectors are working but the engine doesn't fire, so that may be an easier test than pulling the injector rail.

Just a thought - some markets have an injector dropping resistor, an oblong aluminium box bolted to the inner fender panel which plugs onto a 6-way connector. Are there any stray plugs/components in the engine bay?

If everything still checks out, and your valve and ignition timing prove to be spot on, then I would see if you can find a known, good distributor to swap out with yours. As I said previously, the distributor contains the crank angle sensor and if this isn't working properly, your injectors will be firing out of phase, if at all.

Best regards, Clive
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Post by impulsive » Wed Jun 13, 2012 8:20 am

IPTOC wrote:Certainly sounds like you've tried pretty much everything.
Yeah, I feel like I have tried everything as well. Its pretty damn frustrating.
IPTOC wrote:Your spark plugs will be wet if the injectors are working but the engine doesn't fire, so that may be an easier test than pulling the injector rail.
True.
IPTOC wrote:Just a thought - some markets have an injector dropping resistor, an oblong aluminium box bolted to the inner fender panel which plugs onto a 6-way connector. Are there any stray plugs/components in the engine bay?
Yes, I do have a dropping resistor under the hood. I need to check it following the manual's instructions. And yes, I do have a few stray plugs under the hood that I am unsure about. I think most (all) of them are for the air conditioning which I removed or for options my car doesn't have (like AT). I will take some pics of the mystery wires nonetheless and see if we can ID them.

Thanks - Bart
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Post by impulsive » Sun Jul 01, 2012 11:01 am

OK guys, I know its been a while, just had to walk away from it for a few weeks. The frustration is causes is like nothing else. :drinkers:

OK, I took the valve cover off again and had another look at the timing. I think I have it right. The part I guess I just really don't understand is, how the hell do you know if #1 or #4 is ready to fire? From wedge's first post:
wedgenut wrote:Then look at the cams and see what position the lobes are in. No 1 should be valves "on the rock" in other words one valve just closing and the other just opening. No 4 should have both valves with clearance.
I think I have this right. The lobes are basically right at #1 and #4 looks like the lobes are not in sight. I took some pics and I know it will be hard, but maybe you guys can tell if I have this right. Every full rotation the valve appear to be in the same configuration.

Also concerning the dizzy. When I slide it in, I can get the rotor to point just about right at the #4 lead. From the angle I can view it, it looks like it is just about to hit #4 which I think is correct.

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#1
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#4
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Post by wedgenut » Sun Jul 01, 2012 3:44 pm

Righto it looks like your cam timing is correct and from what i can see No1 cylinder cam lobes appear to be on the Rock, what this means is that one valve has just closed and another is just starting to open, if you move the crank back and forward just a few degrees you will see the valve rockers moving up and down where as the ones on No 4 won't show any movement.

So you do have it at top dead centre on No. 1 and No.4 and it looks like you have No. 4 on the firing stroke so all is ready for the distributor, Forget about pointing the rotor to any particular plug lead. I did explain how to set the distributor already and it IS also in the manual. On the distributor shaft there is a small indent or pop mark. It must line up with the pointy bit on the casting in your picture when fitted. Remember it will rotate as the gear meshes so wind it back a tooth before you push it in and the mark should line up. If it doesn't then repeat until it does.

I can't quite see in your picture if this is the case but if it is then all is well and it can be buttoned up.

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Post by impulsive » Sun Jul 01, 2012 4:14 pm

OK then, this is the only thing that stands out on my dizzy's shaft:

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So, that line needs to line up with the raised area in the head casting that your arrow points at? It's almost perfectly in line with the flange mark, but not quite.

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You say to ignore the position of the rotor contact, but shouldn't it be ready to hit #4?

Going to bed now, I'll button it up in the morning and have a go at starting it.

Thanks- Bart
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Post by wedgenut » Sun Jul 01, 2012 5:00 pm

Yes you are correct, the rotor should be about to hit No. 4 but if the procedure is to set it exact by the marks why wouldn't you do that. Then you know you are close enough for final timing. The mark you indicate is not on the shaft, it is on the housing. here is a picture of the alignment mark on the shaft. If you don't have this mark I question what distributor you have because I have never seen one that doesn't have this. My Impulse manual shows this mark as well! sorry about crappy picture

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