Timing problem

[8upZR1]

After fixing a blown head gasket on my 90 it has been unable to start. Many good suggestions were made on the other thread I started. Today I cranked the car with the plenum removed to check out the injector spray pattern and I was greeted by combustion from the injector housing ports. All 8 cylinders are firing, its just that the combustion occurs in the ports and not the chamber. Can anyone tell me if this is an ignition timing issue or if this is a cam timing issue? I am stumped.

[ZR1 MK]

Based on information here and your previous post, I would check the combustion chambers with a scope viewer to see if any valves arent fully closed or bent at TDC due to a slipped cam. Or check compression and or leak down if you dont mind cranking the engine, but Id go with the other option first. If all checks machanically, start diagnosis on the ignition timing again.

[8upZR1]

I have a boroscope, just need to find all the pieces. I dont think any valve damage occured, before firing the motor spun nicely by hand, and while cranking I have never noticed anything that would be worrisome. I cant think of anything that would cause my timing to be so far off though. For combustion to exit the ports, the spark is occuring sometime while the intake valve is open. About as far as you can get from correct timing. Compression has always looked good, leakdown I have yet to do.

[ZR1 MK]

If all checks mechanically, it should be an electric issue. What is the MSD box you mentioned in your other post?

[8upZR1]

I use an MSD DIS 4+ box. It converts the ignition to a cd setup and ups the voltage from the coils. It has some nice features like multiple sparks, rev limit, 2 step, high speed retard, tach output. IMO it is a necesity if you are running nos. I have been running this igntion on my mustang for years now and have no complaints about it. I am surprised that more ZR1 people do not know about this box. I mentioned it to Haibeck and he kept asking me how I run an MSD without a distributor.

I am beginning to think that it would be impossible for the timing to so far off from an electrical problem. I am going to pull off the valve covers and recheck the cam timing. I was told that when using a crank locking device that it would only fit into one of the slots machined into the reluctor wheel, but now I am thinking that this advise was BS and that I locked the crank down in the wrong location. I did not even think to check this because the info came from a source who has always received the highest praise from the people on this forum. I am beginning to think this was a load of bs.

[ZR1 MK]

My engine builder uses that same ignition box.
The crank has a variety of slots, but only one that is deeper than the rest. It lets the crank locating tool make contact with the block, where the other slots wont let the tool set 100%. Its at 51 degrees. This could be the problem. Do you recall?

[8upZR1]

That is what I was told so as soon as the base of the locking pin went all the way to the block I figured I had found the one deep slot. When I bolted it down it was sitting pretty, flush against the block with no gaps or space whatsoever. I am now thinking though that this is a crock. Any of the slots is deep enough for the crank tool to fit into. Today I am going to redo the cam timing and I will find TDC on #1 and then rotate backwards 50 degrees and look for the nearest slot. I should have done this the first time, but hey, this is the first time I have played with an LT5. This time around though I will set the cam timing as the factory does it. No degree wheel and no hassle, just line up the holes, pin the cams and torque down the bolt. I do not want to do this crap a third time so I will go with what I know the car runs with. If my wife does not come home from work early I may be done by sundown.

[8upZR1]

BY the way, who is your engine builder? What combo are yuou running in your ZR1? ARe you happy with what you have?

[ZR1 MK]

I would have confirmed the crank position at 51 degree regardless and checked everything many times. I was thinking of doing the cam timing on my own, but probably will have everything assembled by the engine builder.
My current engine only has ported plenum and injector housings with modified exhaust. Pics and list of mods is shown in my webpage. This link http://www.cardomain.com/ride/418999/4 will take you to the specs for my new 427 engine.
Good luck with the cam timing. I heard its a pain with the engine installed. Or maybe you plan to pull it. I have info on doing it with a cam coder if do it installed and your interested.

[8upZR1]

427 sounds like a monster, that should be a hot ticket. I am doing this with the motor in the car. It is semi painful, but I am married and have therefore an amazingly high threshold for physical and mental abuse. I have already started the process, in fact the cams are already timed to the factory settings. All that is left to do is put back the valve covers and all the other pieces and do-dads. I decided to not mess with degreeing with a wheel cause I would only degree to factory specs anyway since this has been such a nightmare. I checked about a million times that I was in the right slot this time. If I put this motor back together and it still does not run I will be extremely angry that I gave up my performance cam settings for factory specs and still nbeed to hunt down some ignition gremlin. What is a cam coder? I have never heard of this. Do you mean the cam specs? I have those, the cams look cute on paper, very gentle. Anyway, time to play with the little one. I will update on tomorrows starting attempt.

[ZR1 MK]

Typo on my part. It a camcorder to view the timing marks during the timing process. To ease your mind, all the info I have read over the years tells me agreesive cam timing isnt much of an advantage. Let me know the results.

[8upZR1]

Last time I did the cam timing I used the camera on my cell phone. IT actually worked very well. I have started to put the pieces back together. All that is left now is the tensioner, AC, alternator, PS pump and plenum. With some luck and a lot of red bull it should be done by tonight. I will post the results.

[8upZR1]

Apparently a higher power does not want the car to start. I finished the cams and was about to start the car. The last thing to do was attach the battery cable. I put the negative terminal up to the post and was greeted by an electrical arcing sound, lots of smoke, and massive amounts of battery acid. It came from behind the battery, from the electrical junction box. At this point I am assuming a + wire broke and hit the chassis. This is strange because after I put the power brake booster back I installed the driver seat and used the battery to move the seat back to gain access to the front bolts. After this I did no more work in the battery area. After this it was late and I said no more. So today hopefully will be the day.....

[ZR1 MK]

:thumbsdo: Let us the results on your problems.

[8upZR1]

Once again this has all been a giant waste of time. The cams are timed to factory specs now and the motor still wont fire. Still I get combustion through the intake ports. This time I made absolutely 100% sure that the crank was positioned in the correct orientation, and the locking pin sat totally flush against the side of the block. The cams were pinned and the manual tensioners were set. I triple checked everything before torquing down the bolts. So I guess I can rule out cam timing. Back to playing with ignition related components.

The short circuit problem was caused by the alternator. Where the power wire hooks up there is a plastic or rubber piece that isolates the mounting stud freom the rear of the alternaotr case. This somehow broke off of my alternator and therefore caused the power wire to ground. When I attached the battery cable the orange "safety" portion of this wire at the junction box fried itself. It was a quick problem to fix but I had to go and exchange my battery for a new one as it was leaking acid like no other. I strongly suggest that anyone playing with the alternator pay attention and make sure that this isolator bushing is in OK condition.

As for my initial problem, I am now totally out of ideas. It was stated some time ago on this thread that the crank sensor could possibly have the wrong polarity. I checked the new sensor against the old one and discovered that the business ends repell each other, so the magnets are properlly inserted. I was wondering if it is possible for the polarity to somehow swap. It was posted that the sensor could be rewired if the magnets were improperly positioned. I was thinking that maybe I should rewire the senors to see if this brings the timing into its normal range.

Regarding the cam sensor, is it also a magnetic sensor like the crank? Mine show no magnetic properties but I am not sure if they are supposed to. I cannot think of anything else that would throw off the timing by that much.

If I were to send somebody my ECU and ignitoin module would anybody be interested in installing them on there car just to see if they are good? I am positive that they are but now I am pissing in the wind.

[Tyler Townsley]

I know you are frustrated, it took me 2 1/2 years to finally get the prototype running. It is very difficult to troubleshoot a problem alone once you have beat your head against the wall that long.
If the cams are right then you are back to the dis/ecm/sensors/plug wiring. I would start with the wireing. Do not go by the numbers on the coils, get the manual and check against that. The next check is to use the dis checker with a scope to check the sensor input and isolate the problem to the dis or ecm. I suspect the dis.
I can lend the checker and scope, pm me an address and I will try to get them packed for shipment this weekend and shiped next week

Tyler

[8upZR1]

thankyou Tyler, that is very generous of you. I will PM you shortly. I am thinking about making a timing adjuster for the lt5. It would consist of a reluctor wheel mounted on the snout of the crank and an udjustable sensor mount. This way base timing could be changed by either moving the wheel or the sensor. If I made a few of these would anybody be interested?

[ZR1 MK]

If I were to send somebody my ECU and ignitoin module would anybody be interested in installing them on there car just to see if they are good? I am positive that they are but now I am pissing in the wind.
I would be willing, but Im not local.
How is your progress.
What do you think was the cause of the gasket failure?
Was the car running properly before you gasket issue?

[8upZR1]

Progress is bad. Tyler, thankyou so much for the scope and ISS, unfortunately everything looks to be good. I cannot simulate engine rpm's low enough though, even on the crank setting the ISS is simulating rpm's high enough to trigger the 5v bypass. Whenever I try to start the motor it never sees enough RPM to get out of bypass mode. MAybe I will try putting 5v on the line myself while cranking, hope this does not fry anything.

The car was running great before the head gasket failure. Absolutely no problems except for some minor issues. Those being poor performance, most likely caused by the secondary ports being completely clogged with carbon, and another problem that was temp related. The car was only fast when the temp was very high. With the water temp in the middle or low range the car would shake and not go anywhere, kinda like the secondaries were not opened, but worse. Once it heated up the problem was gone. With a Haibeck chip the temps stayed so cold the car never ran hard, so I switched back to the stock chip. I assume maybe problem 1 and 2 are related but no telling until it starts.

The cause of the head gasket failure was from using a coolant additive from Royal Purple called Purple ICE. The coolant used has always been the green stuff mixed with distilled water, and absolutely no deviations from this. I added Purple ICE to the mix cause the stuff did good on my Mustang, but a mere four days after adding it the gasket blew. There was bubbling and corrosion on the gasket, and the fire ring on one cylinder had given way. Coolant poured out of the exhaust pipe and I knew it was fatal. On the forum on the EES mods web site they have pics of a gasket that was used with dex cool that suffered the same fate. My gasket looks exactly like that one but with more corrosion. My car has low miles and the gasket looked worse than one from my old Mercedes diesel with 300K miles on it. Very scary. Royal Purple is ussually a decent brand and I like their oil but stay the hell away from the Purple ICE coolant additive. It will eat away a gasket in no time. Mine was gone in 4 days. I guess in the end it was good though cause I never would have gotten the ports cleaned out and ported unless a major catastrophe like this occured.

Since I have rebuilt the top end of the motor I have not changed anything in the combination so I do not understand why the problems are now occuring. It ran beautifully before this. I am wondering if this bypass mode thing has something to do with my problem. Is there any way to tell what rpm the ISS is simulating? My tach does not work, so it is no help. Maybe I can push start the car from 20 MPH or so to see if it will start then. If I apply 5v to the bypass line to get the DIS to switch to EST mode will it work even though the motor is cranking at less than 400 rpm? SHould it be cranking at less than 400 rpm? I am upset.

[Tyler Townsley]

I should have kept all replies in this thread, sorry. Do not try to push start the car! Let me see if I can get another mind to look at what is happening for some fresh thought.

Tyler

[8upZR1]

Yes two threads is confusing. But I have so many questions, I felt I needed to start anew. I just looked at the Prototype page, sounds like an awsome piece of machinery, I hope you get it all squared away. Sure I will wait on the push start, is there something bad that could happen from doing this? Other than me having to push start the car wherever I go, cause if thats what it takes I will do it. Any fresh thoughts or ideas about this woyuld be extremely helpful. I will let you know about the signal comparison tomorrow morning.

[Tyler Townsley]

Quote' What about a bent pin on the DIS connector? It is really easy to do,
especially if he has been swapping modules out.'

Unquote

Tyler

[8upZR1]

All pins look good on the DIS and the ecu. I check every time I pull the connectors. The fact that the dis diagnostic connector functions properly tells me that there are no problems with the harness making contact with the pins on the DIS and ecu, unless of course they do not run to the connecotr, but everything looks good at the harness.

[8upZR1]

I have been comparing the signals from the ISS and the crank sensor with the oscilloscope and cannot get them to match no matter how hard I try. The ISS will not produce the sharp wave that the Sensor will. It is more of a rectangular wave. Maybe I am not usibg the correct setting. My crank sensors don't seem to produce as much voltage output as they should be. Resistance is good, but the factory sensor does not even show output on my Volt meter. The new sensor is only putting out .5V. The page from the manual says .8V to 1.5V. The factory sensor is shorter than the new one, and it also had a shim. The .5V from the new sensor was without the shim. It is lower with the shim. I am thinking maybe I should find a third crank sensor. The square wave from the ref out line does not match the signal from the est line. According to the manual the signals should be identical but the est signal should be advanced in time. I am getting that the est signal is a shorter wave than the ref high. Is this normal or should I look into this?

I was wondering if there is any way that the reluctor wheel can be damaged, or if it is possible that rust can disrupt the signal? I doubt it could happen but maybe water from my head gasket incident rusted the wheel. Unlikely but anything is possible at this point.

[Tyler Townsley]

You do not have a wheel the crank is formed with detents for the sensor to work from. One of the reasons for the pigtail was to make sure the crank sensor was not still in the system as I think it will effect the ISS voltage. Its been a long time since I looked at the signal.

863-428-1410

Tyler

[8upZR1]

I removed the crank sensor when using the ISS. Using the scope, I compared the output of the ISS to the output of my crank sensors as the motor turns over. They are not the same. Maybe I am doing something wrong. I will repeat the procedure tomorrow with greater emphasis on all the little details. If the ISS truly is putting out 400 rpm, and my ignition thinks it is seeing 1800 then is it the DIS? I would assume so since the signal goes there first and gets processed into the ref signal. But I think it is highly unlikely that my good DIS with only a few hours of operation would break and that my brand new spare has the same strange and uncommon problem. I guess it could happen, especialy if I fried both of them when I tried to use them without the internal ground hooked up. When I crank the engine with the crank sensors there is no rpm readout from the MSD for some reason. Just by looking at a spark plug against the intake manifold it is obvious that it is much slower than the ISS. Probably closer to 400, but maybe even slower. At 400 rpm there should be 6.6 sparks per second. It is definetley much slower than this. What speed should the starter spin the motor to if it is getting 12V? I am leaning towards trying to start the car with a 30 mph push from a truck. That way I would know that the engine rpms are above the bypass rpm.