1994 stalls, no codes and restarts no problem
07-29-2015, 03:28 PM
#41
Solderhead, very interesting. Maybe it is my old mind and all the days with carburetors, but if you had four bad injectors wouldn't the car run rough most of the time? Wouldn't you set a lean code at some point? And if the injectors were going up to 100% duty cycle, wouldn't you stall more frequently at higher speeds where more fuel was required. I am not doubting what your saying, just having a difficult time understanding the logic. But then again sometimes the C4 defies all logic.
Her car only has 89,000 on it. I changed my injectors just because on my 95 with over 160,000 and they were the originals. I just went out and checked each injector. They all read 12.78 +/- .01. Granted this is the duty cycle you have referred to in you post.
I REALLY appreciate your writeup. When your trying to solve a problem it helps to have options to explore. Can you explain to me in detail how you tested the duty cycle of each injector? You indicated you tested the injectors and the car stalled with your test showing an increasing duty cycle. We can't get the damn car to stall on any consistent basis, if we could that would point us in a direction.
Her car only has 89,000 on it. I changed my injectors just because on my 95 with over 160,000 and they were the originals. I just went out and checked each injector. They all read 12.78 +/- .01. Granted this is the duty cycle you have referred to in you post.
I REALLY appreciate your writeup. When your trying to solve a problem it helps to have options to explore. Can you explain to me in detail how you tested the duty cycle of each injector? You indicated you tested the injectors and the car stalled with your test showing an increasing duty cycle. We can't get the damn car to stall on any consistent basis, if we could that would point us in a direction.
Just a quick thing to think about: firing order is 1-8-4-3-6-5-7-2.
Now let's say the injectors on cylinders 8,4,3, and 6 are failing. You've got 4 power strokes in a row that were not able to fire. Again, that's just example. I'm not saying that's what's going on, but it's definitely something to rule out. That particular situation baffled me for three days before I narrowed it down. I'll elaborate some more when I get home. The vehicle didn't really have much stumbling or rough running, but did have the occasional misfire. Enough to drive one to drinking!
07-29-2015, 04:28 PM
#42
Le Mans Master
Thread Starter
I am pounding sand and drinking....nothing seems to help. As noted, I check the resistance on her injector and they are all close. Nothing like your 10% deviation which started you exploring the injectors as the issue.
Thanks,
John
Thanks,
John
07-29-2015, 07:34 PM
#43
As far as duty cycle, make sure your DVOM has duty cycle capability. The easiest way is to back probe the connector and watch it while running, and it should give an idea of what the PCM is trying to do with it.
If that seems ok, yet another possibility is to remove the injectors from the base, disconnect the ignition coil, and physically watch the fuel injector spray pattern while you have someone turn the key and crank the engine. Sorry if this seems incoherent, it's been a long day and I'm still not home.
07-29-2015, 09:27 PM
#44
Le Mans Master
Thread Starter
My meters do not have this option. When I tested the injectors, the engine was warm, not hot. It had been driven about 15 miles to my shop and had sat about 30-40 minutes before I tested them. So far the car has not stalled. But the last time it was a 11 day stretch. It is a waiting game now to see if anything happens.
Know how you feel. I average day is 10 hours 6-7 days per week.
Know how you feel. I average day is 10 hours 6-7 days per week.
07-30-2015, 10:18 AM
#45
Safety Car
years ago I made a DIY injector flow tester. Here it is and it cost about $15.
Now I had an Actron Fuel Injector tester that would pulse the injector and used a graduated cylinder to collect the water. I measured the fluid produced by 10 pulses of the injector. Most home water bibs produce about 65 lbs of pressure, so I would simply hook this up to the hose bib and open the faucet until I got 45 psi and that replicated by fuel pressure. I would activate the injector with the Actron 5 ms pulse 10 times and see how much fluid was produced by each injector. Kinda back yard but it worked for me.
The other idea is simply to pull your injectors and put them in her car for a day and see what happens. Good Luck.....I hate intermittents.
Also, if it turns out to be injectors, let me know. I can't imagine that I don't have a couple of sets of stock LT1 injectors at the shop. Both my LT1s are 383s and are running the 30 # Ford SVO injectors.
Now I had an Actron Fuel Injector tester that would pulse the injector and used a graduated cylinder to collect the water. I measured the fluid produced by 10 pulses of the injector. Most home water bibs produce about 65 lbs of pressure, so I would simply hook this up to the hose bib and open the faucet until I got 45 psi and that replicated by fuel pressure. I would activate the injector with the Actron 5 ms pulse 10 times and see how much fluid was produced by each injector. Kinda back yard but it worked for me.
The other idea is simply to pull your injectors and put them in her car for a day and see what happens. Good Luck.....I hate intermittents.
Also, if it turns out to be injectors, let me know. I can't imagine that I don't have a couple of sets of stock LT1 injectors at the shop. Both my LT1s are 383s and are running the 30 # Ford SVO injectors.
Last edited by pkincy; 07-30-2015 at 10:21 AM.
07-30-2015, 03:45 PM
#46
Le Mans Master
Thread Starter
We are waiting to see the results of the fuel pump change. If I swap injectors, it could very well be 2-3 weeks before we know anything....or my car dies! 
07-31-2015, 05:02 PM
#47
Le Mans Master
Thread Starter
Okay, we can now rule out the fuel pump and wires.....sucker died today after changing the pump on Tuesday and cleaning all the electrical connections to the pump inside the tank and out.
08-02-2015, 06:34 PM
#48
Have you checked the adjustment for the ignition switch rod and the condition of the contacts on the switch?
08-02-2015, 07:05 PM
#49
Cruising
Member Since: Jul 2015
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1994 stalls, no codes and restarts no problem
Just curious, what is the outside temperature when the car dies? I think I saw it mentioned that idle fluctuates and when stopped. Mine is was not dieing but really bad idle in drive when hot out. Turns out to be the ECM. Just something to consider.
08-02-2015, 11:16 PM
#50
Le Mans Master
Thread Starter
There is no issue with idle with her car and stalling. It will stall at idle sitting at a light, doing 30-40 MPH down the street or 65 MPH down the freeway. We hit some hot days where it was in high 90's. But there was no correlation to outside temp and stalling. It would stall when it was only 60 out or 90. It would stall twice in a 15 mile trip to my shop at 2:00 and then on her way back when it was warmer out the 15 mile trip would be without an incident. We had the fans changed a couple years ago to turn on early. The car seldom reaches 207 max when you drive it, so it is not getting hot.
The prior owner of my 95 lived in Arizona and there were issues with the ECM on hot days. Hot there is like 112-116. He discover the temp cure by spraying the ECM with a spray that dropped the temperature or putting iced towels on the ECM. It would then start and run. But the ECM had to cool down before the car would start. Similar symptoms to a Opti failure. In the case of the 95, replacing the ECM solved the problem. But in the case here, the car stalls and will start right back up with no waiting period needed.
The prior owner of my 95 lived in Arizona and there were issues with the ECM on hot days. Hot there is like 112-116. He discover the temp cure by spraying the ECM with a spray that dropped the temperature or putting iced towels on the ECM. It would then start and run. But the ECM had to cool down before the car would start. Similar symptoms to a Opti failure. In the case of the 95, replacing the ECM solved the problem. But in the case here, the car stalls and will start right back up with no waiting period needed.
08-03-2015, 08:45 PM
#51
Le Mans Master
Well Brother John I cannot give you any advice since I am having the same symptoms you two are having can you believe it! One thing is that I got a SEL and a code H16 which I cleared and didnt come back.
08-04-2015, 10:41 AM
#52
Le Mans Master
Thread Starter
Kimmer, Opti guy that has been making suggestions suggested this.....
In the past I have used 12 volt dash lamps connecting them to a couple of key terminals, then they are placed in the wiper cowl area so they are easily seen. One to PCM 12 volt battery power another to PCM ignition power supply for example. I also tap into the fuel pump 12 volt supply wire at the oil pressure sending unit to see if any of the circuits lose power when the stall occurs. I'm thinking it would be smart to limit the amount of warning lamps to make it less confusing. In other words it may take a couple of placements of the warning lights to find the root cause.
Sounds like a smart idea....just don't want to start cutting and splicing wires if I can help it. Ordered a OBD1 16 pin cable yesterday (94-94 use OBD1 not II). Looking at trying to get some data logging when it fails to see if that would point us in the right direction.
BUMMER about the Solano Autocross. Missed the last two. Out of town on the first and trans/clutch issues on the second. Was hoping I would have the car back for this month's fun.
In the past I have used 12 volt dash lamps connecting them to a couple of key terminals, then they are placed in the wiper cowl area so they are easily seen. One to PCM 12 volt battery power another to PCM ignition power supply for example. I also tap into the fuel pump 12 volt supply wire at the oil pressure sending unit to see if any of the circuits lose power when the stall occurs. I'm thinking it would be smart to limit the amount of warning lamps to make it less confusing. In other words it may take a couple of placements of the warning lights to find the root cause.
Sounds like a smart idea....just don't want to start cutting and splicing wires if I can help it. Ordered a OBD1 16 pin cable yesterday (94-94 use OBD1 not II). Looking at trying to get some data logging when it fails to see if that would point us in the right direction.
BUMMER about the Solano Autocross. Missed the last two. Out of town on the first and trans/clutch issues on the second. Was hoping I would have the car back for this month's fun.
08-04-2015, 12:46 PM
#54
Le Mans Master
Thread Starter
[QUOTE=pkincy;1590196407]An OBD1 cable is necessary but since you have an obd2 pin out you will need this inexpensive gender changer. Amazon has them.
Cable I ordered is already set up, don't need a converter.
Cable I ordered is already set up, don't need a converter.
08-04-2015, 10:10 PM
#55
Le Mans Master
Well after reading all pages, most of the normal things are covered. But since it's a 93 it uses a ECM which has a reputation for intermittent, strange engine running problems. It might drop the pulses to the ICM or drive for the injectors plus other wonderful events.
A lot of people have tries cold packs or such to try to conform or not the ECM as the root cause of the problem. It would something to consider other than bad connection or like an ignition switch.
***EDIT***
Forgot what I said.
Somehow I thought it was a 93 (possible read another thread). The 94 obviously has a PCM which does not have the weird problems as the ECM.
So I will stand corrected on this and watch for the solution.
A lot of people have tries cold packs or such to try to conform or not the ECM as the root cause of the problem. It would something to consider other than bad connection or like an ignition switch.
***EDIT***
Forgot what I said.
Somehow I thought it was a 93 (possible read another thread). The 94 obviously has a PCM which does not have the weird problems as the ECM.
So I will stand corrected on this and watch for the solution.
Last edited by pcolt94; 08-06-2015 at 09:50 AM.
08-11-2015, 05:17 PM
#57
Le Mans Master
Thread Starter
Kimmer,
No update as of today. I received the cable to hook up to the laptop. Downloaded Tunerpro RT into laptop. Not a lot of directions on this. Lynda will be in tomorrow so I am going to hook up to her car and see if I can download data. Car has not died since the last time....right after installing the fuel pump. But this is the way it goes.....days with nothing and then stall out of the blue.
Will keep you informed.
-John
No update as of today. I received the cable to hook up to the laptop. Downloaded Tunerpro RT into laptop. Not a lot of directions on this. Lynda will be in tomorrow so I am going to hook up to her car and see if I can download data. Car has not died since the last time....right after installing the fuel pump. But this is the way it goes.....days with nothing and then stall out of the blue.
Will keep you informed.
-John
08-13-2015, 07:35 PM
#58
Le Mans Master
Thread Starter
update 7/13/2015
Lynda brought in her car today and we hooked my my laptop to do some data logging using Tunerpro RT. What a challenge with the software. We could see data being read, but could not figure out how to view it. Tried several things, but none worked.
After that I tried one more time to pull any error codes. Well S**T...up pops H41 and H72. Historic codes. The 72 refers to transmission error but the error would result in "delayed or soft shift into 3rd". Don't know why that popped up.
Code 41.. "the PCM will disable the fuel injectors to prevent flooding of the engine." This is the first positive lead. Now just have to figure out exactly what is happening. According to the FSM "the code will set when voltage on circuit 423 exceeds 4.6 volts and engine speed is less than 1500 RPM".
So at some point the voltage on this circuit is over the 4.6 volts, but happening days apart. How do you put a finger on this to determine what the trigger is?
After that I tried one more time to pull any error codes. Well S**T...up pops H41 and H72. Historic codes. The 72 refers to transmission error but the error would result in "delayed or soft shift into 3rd". Don't know why that popped up.
Code 41.. "the PCM will disable the fuel injectors to prevent flooding of the engine." This is the first positive lead. Now just have to figure out exactly what is happening. According to the FSM "the code will set when voltage on circuit 423 exceeds 4.6 volts and engine speed is less than 1500 RPM".
So at some point the voltage on this circuit is over the 4.6 volts, but happening days apart. How do you put a finger on this to determine what the trigger is?
Last edited by John A. Marker; 08-13-2015 at 09:14 PM. Reason: added quote marks for code 72
08-13-2015, 08:32 PM
#59
Safety Car
My Helms is over at the garage so don't have it handy but google gave me this:
http://tech.corvettecentral.com/2011...trouble-codes/
and that states 41 is an open Ignition Circuit and 72 is VSS loss. Both of which would give you a stall problem.
http://tech.corvettecentral.com/2011...trouble-codes/
and that states 41 is an open Ignition Circuit and 72 is VSS loss. Both of which would give you a stall problem.
08-13-2015, 09:12 PM
#60
Le Mans Master
Thread Starter
pkincy, quotes are from my GM FSM. The 72 code doesn't say anything about stall....just delayed shift or soft shift.
http://www.mifbody.com/DTCs/DTC%2072_A.jpg
The code 41 if the PCM disables the injectors...no fuel....stall.
http://www.mifbody.com/DTCs/DTC%2072_A.jpg
The code 41 if the PCM disables the injectors...no fuel....stall.
Last edited by John A. Marker; 08-13-2015 at 10:13 PM.