No Start No injector pulse (shorted injector) part 1
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- เผยแพร่เมื่อ 2 ส.ค. 2024
- This problem is specific to GM vehicles built from the late 80s through the early 90s. Here is a partial list of the cars that used this style fuel injector.
- 5.0 and 5.7 in the Corvette and Camaro
- 2.8, 3.1, 3300 (Chevy, Buick, Olds, Pontiac)
- 1.9 (Saturn)
- 4.9 (Cadillac)
The first time I ran into one of these, I mistakenly replaced the engine computer in an attempt to fix the no injector pulse condition.
It is strange that one shorted fuel injector can cause all the other injectors to not fire, but this is exactly what can happen with a group fired system. “Group fire” means there is only one transistor in the computer that controls all of the injectors at the same time.
Symptoms
- no start
- no injector pulse
- rough idle
- misfire
- starts and stalls
- failed emissions
Fix
- replace ALL fuel injectors
Tests shown
- how to measure injector current from a common location
- injector current ramp
- injector pulse test with a noid light
- how to verify injector power supply
Related videos
- No Start No injector pulse (shorted injector) part 2
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- GM 3300 Intermittent no start rough idle (shorted injectors)
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- How to test for shorted fuel injectors (1987-1994 GM Cars)
• How to test for shorte...
- Rough idle, false MAP codes intermittent no start (shorted injectors) GM • Rough idle, MAP code 3...
Playlist
- (Chapters 17, 18 and 19) Fuel Injector Testing
• (Chapters 17, 18 and 1...
For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book.
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Disclaimer:
Due to factors beyond the control of ScannerDanner LLC, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. ScannerDanner LLC assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. ScannerDanner LLC recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of ScannerDanner LLC, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not ScannerDanner LLC. - ยานยนต์และพาหนะ
I am just a simple diy guy from Greece and this channel is the best one I have ever came across
Thank you from Greece!
i am an apprentice tech and i am forever grateful for your videos. i am dealing with the hardest p0300 problem ever and your videos are helping me alot. thanks for takin the time to educate the youtube community
Perfect video on how to find shorted injector(s) and how to use scope for that puprpose.
Although dedicated to this specific engine, I think those principles are universal.
Many thanks for that explanation for current waveform ramp!
I agree, there are principles here that apply to a lot more circuits. Thank you!
This video saved me a lot of hassle and money. Thank you very much.
that is correct my friend. If you are zoomed out too far (too long of a time base) a current ramp pattern (especially on ignition coils) can look like a square wave.
Dan, i swapped out some injectors that clicked for the frozen ones as he had an extra TB, made a TB gasket and it just fired it up. I ordered a set of 4 probe pins today from Fluke--
Not sure why someone put such ratty injectors in there but i can tell you it wasn't me, after some guy was looking at it for about a week i took a gander for him-- you taught me a few things, thanks
hey i'm looking to buy a scope, any suggestions? id love to have a one channel ignition scope and amp clamp.
Had a look at an '87 C4 Corvette no-start for a friend yesterday.
The car has been sat for some years.
Initial problem was no fuel pressure, bad pump.
I had spark and injector pulse both banks.
Fitted a replacement, got a couple of psi. Now low voltage at pump due to corroded fuse.
Sorted that, had 45psi.
Cranked and got a bit of life.
By feeling the headers, found only cyl 3 and 5 had fired.
Found a few plug wires on in the wrong order, cured those and got all bank 1 to fire.
Next step was bank 2.
Even though I had seen the noid light flash on a bank 2 injector earlier, I removed and cleaned the fuse. It too was badly corroded.
Next key on, the cooling fan started up and when cranking I had no injector pulse on any bank.
Also the SES lamp was flashing codes 1,1 and 1,2 alternately.
These codes are flashing at every key on, without bridging A and B on the ALDL.
This video reminded me to check again for shorted injectors.
Any ideas on the flash codes?
question about 87 ford f150 good spark no injector pulse, bad pcm ground, what input use the pcm to control injector pulse, what is PIP? is this a crank or cam signal? fix the ground fix the injector pulse but still not 100% how this pcm had good spark no injector pulse..
Dan, my buddy has a 92 GM 2500 pick-up w TBI , he has no pulse, yesterday i tried a test light on bat + and with key on the light is on, cranking NO light- before i looked at it he replaced the fuel pump, and then decided to replace the pick-up which i changed for him, then he changed module, still NO start, i just pulled the ECM for him-- however i was thinking about a short somewhere-- i see pin 14 + 16 for injectors -- the ECM grounds the injectors correct?
or the pick-up coil in the distributor, or a bad module power and ground or an open in the reference wire.
if the ECM responds to the bypass test, this just tells you that the ECM is good and that your problem is in the module/pick-up coil circuit
Hello Mr scanner danner, I really appreciate what u do , what needs to be done when replacing 06 caddilac sts Ecm , I use launch 431x pro, its doesn't even crank, I programmed the instrument cluster to the new vin , but still no luck
Thanks for the video, I have the same thing going on with my 98 3.1 Achieva. It's sequential fuel injector but I'm haveing the same no start situation. Please tell me how I can get your bood
Just wanted to say your videos and tips are amazing, highly beneficial to anyone from diy guys all the way up to experienced techs. I was wondering if you have any advice on buying a scope with amperage capabilities for techs that cant quite afford a Vantage? Thanks a lot for the great informational videos and keep up the good work!
Thanks so much! And yes, I would recommend the uScope master kit. It is a single channel pocket scope. I have some videos showing me using it. Just type in uScope on my channel page.
Here is a link to my tools page where I have this one listed. www.scannerdanner.com/lab-scopes.html
It sells for $399
Awesome! Glad it helped.
hello danner i have a 2001 vw jetta with no pulse and i have tried everything including crank sensor, coil and tested by dealer procedures and i still have not find the problem, i was wondering if you have ever come across this problem with these type of cars
very good video
Redirected from other video,
when my 1987 vette is warmed up, I placed my foot on the floor and it just stayed at 2300-2400rpm backfiring and shaking, and then when I let go(all of this was less than 3 seconds) the RPM shoot up to around 3000rpm then went back to idle.
It legit sounded like it had launch control installed or a WOT box installed, not sure if this could be the issue but I'll check that.
I did scan the car and got these DTC codes:
1) 63 2) 61 3) 54 4) 52 5) 51 6)46 7)36
Quick question to clarify, are you referring to the purple/white hooking into the dist. module? Just want to be sure i am probing correctly
You're a wizard Harry Lol another great video Paul I wish it were warmer out in Connecticut so I can play with the new lab scope I just got. As always thank you for your videos always informative and fun to watch. By the way how do I get your book? And what format does it come in thank you.
I think I am missing something, If you were to suspect a shorted injector on that system It appears you can d/c the main feed connector harness (4 wire connector) to the injectors and check for a grounding pulse there (test light on 12v+) ? That would test the ECM to make sure its "firing" the injectors with just a test light. AND the shorted injector would be out of the picture.
Sorry, i didn't get a chance to see your message as i was outside with it-- he has another TBI unit with visually better injectors so we used a 9 v battery to check and they click, others did nothing and looked horrible, now looking for a gasket so i can reassemble-- we will try it to see if it starts, if not i will go to your next step-- thanks Dan, he/me appreciate your help!! Glad you have a little spare time this afternoon--
Don't have ACTUAL T-pin but something similar
you need to check for injector pulse. disconnect one of the injector connectors, connect test light to BAT (+) and touch on the control wire (i think they are red and blue if my memory serves me correctly) and crank the engine. your test light should pulse. If it does your injectors are stuck shut. you can smack on them with a screwdriver during cranking, it should free them up if this is the case
Oh, for reference in this application providing the ECM is good with no open wires then NO pulse means the module is bad?
Gracias por el video.
Thanks i used that wire, when i REMOVED the test light i heard a humm for about 4 seconds and felt the fuel pump relay was being activated-- like i said maybe 3-4 seconds, saw no fuel or click from the injectors === next step?
no, it is not energized long enough, also I believe it is a 15-20 amp fuse
In order to see the ramp effect of a good injector, one must also have the correct scale on the x-axis (time), otherwise if the scale is too large, you might not see the ramp and just see the spike, right? Looks like you have about a 10ms scale on the screen there.
Thanks for the video. I have a 1993 Opel Vectra A 2.0i cat. vehicle. It has a Motronic M 1.5 fuel injection system. Do you have any experience with that system? (Does it have any known issues with it? Is it reliable?) I'm just asking out of curiosity. I enjoy watching your videos. They are very informative, and educative.
Hi Paul, great video! What if I disconnect the control wires at the connector and connect a testlight between the feedwire and the negative control wire? Would I see a flickering light? This would verify the control signal from the computer, because the injectors are all unplugged. Of course this would also be possible if you disconnect all injectors and put a noid light or test light on one of the connectors. But since they are difficult to reach, it would be the much bigger effort.
Wouldn't a shorted injector/ injectors pop a fuse?
sorry, I think you did this. Lets do it differently, leave injectors plugged in and backprobe the connector (use a t-pin) one wire at a time. during cranking one side of the injector connector should stay lit and the other side should flicker. (test light to battery NEGATIVE this time)
good evening please i have a question about my car vw touran 1.9 tdi 105 hp start difficult and its cut when I roll I passed the vagcom gave me p0303 and what can be an injector that blocks the start I need your help thank you
go to my friends channel th-cam.com/channels/iFSILHjs5XZecZJDwn7ieA.html
He is a former student of mine and is a VW Master tech. He can definitely help you more than me. I do not work on diesel engines at all.
I'm having the same problem on my Mercedes v6 left bank is working right bank it's not working no injector activation jus do no how to fix the issue
holy shit nice video!
ok, that means the test worked and the ECM did receive the RPM signal. This is why you heard the fuel pump run. The injectors should have also fired. I have NEVER seen the injector drivers (ECM transistor) go bad on this design. I would be more concerned with wiring or mechanically stuck shut injectors. Did this thing sit for a long time? If so the injectors are probably stuck shut from a varnish build up (old gas).
Thank you for teaching me so much in the last two hours. But I do have a problem with a 1997 jeep wrangler and using my node light I can see my jeep's injector pulse cut out after the engine starts. I never lose power to the coil and I can keep it running with a outside fuel source directly through the intake. Most sensors are new except map, temp,. Change out pcm programmed to vin, idle speed.p❤
sensor throttle position, and O2 upstream. Continue to have start then stall by injectors losing power. I am thinking it is a shorted map sensor but almost broke already. Do you have a video that relates. Your videos are great.
Losing power or losing control?
Do you know if the spark drops off the same way?
Ok, now he has pulse and you are probably right with the stuck/frozen injectors, this truck is MICKEY MOUSE to the maxx, thanks for you help, so in conclusion ECM wasn't the problem?? I will try to take a look/remove the injectors for him now, i'll let you know the outcome-- i know i can check injectors with a 9 v bat.. can i use the truck batt??
yes
yes. here is a test for you. key on, engine off. connect a test light to BAT (+) and touch on/off the purple white wire coming out of the ICM (ignition module). (Make sure everything is plugged in) This will provide the ECM with an RPM signal and the ECM should respond by firing the injectors. Let me know the result
no problem glad u fixed it
oh and my name is Paul. :-)
I got water damage in my 1993 BMW 320i. I am having 0.333volts on my injector power line (red/white) instead of 12volts when key is on ON position. Hope i will be able to fix the corroded SMD components
The car is having spark and is cranking but not starting. Now I see it's the DME fault. Water enters the DME bay and it's starts to go bad
what's the device you are using
would you care to share an Amazon link
For which part. The scope?
IT is a crank signal. No cam on this design. You still had good spark because the PCM doesn't control the spark during cranking. Watch my GM Bypass ignition system video. IT is similar to this Ford.
Mine flashing when cold engine but when warm stop flashing when idle. Only 3 and 4
What is the problem it is pcm?
Could be intentionally being turned off to protect the cat from the misfire. Check spark and compression
Hello, Paul. I am just trying to understand something from the video. You stated that the driver does not carry enough current, limits current flow to protect itself from the overload. Do you mean that the driver was not designed to handle that much current and the PCM limits current flow to protect the driver from the current overload?
I would really, really appreciate your answer.
yep, watch part 2 th-cam.com/video/3gTLY6vsxMg/w-d-xo.html
It will answer your questions I am sure.
Thanks, Paul. I have just watched it. What I was trying to know was: Is it the driver that limits the current to protect itself or the pcm that limits the current to protect the driver?. Since you kindly answer yes to my question.You made my day.
Well to be technical, the driver is inside of the PCM, so to me they are one in the same. How the driver is being protected? Now we are talking about something I am NOT an expert in. Electronic engineering is where we are now with this conversation.
You answer is good enough for me. You are the one that I follow the most. To me, you are the best. On my way to the forum now.
Hey, Paul. Current follows the path of least resistance. Usually, fuel injectors are in parallel. We would expect current to flow to the injector that is shorted and not to the other ones causing a fuse to blow, right? I may search in your premium channel again tomorrow to see if I can find series, parallel stuff.
You're forgetting one thing, the driver is limiting the current flow, way before the fuse would blow 🙂
Chapter 16 playlist both here an premium for more on this my friend. Thank you!
Ill have to try this. Tried to fix a leaky injector and after putting it back the engine wouldnt start. I didnt know one bad injector would stop the whole car. I was thinking to myself even if 1 injector is bad i still have 7 more. I was blaming ecu or a list of other stuff
On these early group fired injection systems only. What are you working on?
Could you have ohmed the injectors and possibly found a shorted injector that way? That is if you can get to the injectors
Nevermind you answered my question in the end lol
With the injectors and rail out can I plug in one injector at a time and get it to pulse or do they all have to be plugged in for it to pulse trying to figure out if I have bad injectors or a bad computer with very basic tools
Measure each injector with an ohmmeter first. They should be 12.6 ohms each
Ok thank you
5 reads 11.9 and 1 is 12.2
@@ablanchard3068 so that doesn't sound too bad, but temperature can be a factor on those as well. Resistance can be good at room temperature then with heat from the engine and from current flow they fail. If it is a flat no start right now, I'd move in another direction. Do you have spark? What are you working on?
I have spark and feel pressure there is a new fuel pump in it I put fuel down the plug holes and it burned off the fuel so I took out the fuel rail and injectors and they are not spraying I can manually make them spray but they won't spray when hooked to the car and the car is a Beretta gtz
2002 tahoe 5.3. I lose injector pulse right after starting. Like if the computer shuts it off. I checked for codes and there are non. Bcm does not have any theft codes and engine no crank sensor codes. I replaced the crank sensor but still not starting. Any ideas?
Are you losing spark too?
@@ScannerDanner no I can start it with starting fluid. It's like it starts for 1 second then shuts off The scanner says fuel disable active then shuts off. But there is no time out cus it will start it for 1 second everytime before it shuts off. Also, if I disconnect all the injectors, I don't loose injector pulse while cranking.
@@Jaguarspaw5 can you scan other modules? other than the ECM? This sounds like a theft issue
@@ScannerDanner yes I can scan the bcm and brake control module. I agree. I looked at the data in the bcm security part and it disables the fuel every time it starts bit doesn'tgo into lock put mode. How would I go about testing the pass lock sensor in the steering wheel column? Well I at least know what direction to go now. Thank you for the reply.
@@Jaguarspaw5 I think the instrument cluster is responsible for the anti-theft part? I need to look up service info for you. Let's move this to my forum www.scannerdanner.com It is free to join and I can help you better there. Let me know when you post it and include our conversations in your post okay?
PRODIGY Sir ScannerDanner
Tutorial great thank you very much helpful video .take care
PRODIGY Sir ScannerDanner
From Nick Ayivor from London England UK 🇬🇧
Lincoln ls have a jaguar gen 1 could this b what hes talking about
I've only seen the shorted injector issue on early model group fired GMs
👍👍👍👍👍👍👍👍👍👍👍👍👍👍👍the best🙏✌✌✌✌✌✌
ah ok, I guess the computer is faster acting.
No puls and spark