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Juan Crespo
Juan Crespo, ASE Certified Technician
Category: VW
Satisfied Customers: 1524
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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We have been hunting a few forums as well. Initially we had

Customer Question

We have been hunting a few forums as well. Initially we had no fuel pressure, and no injector pulse, and a myriad of other false codes due to their excessive back probing of the ECU. Now that we changed the ECU we have fuel pressure, and all the pumps energize, but we have no injector pulse. My concern is that when we crank it the oil light flashes. Some vehicles when experiencing low oil pressure will shut down the fuel injectors to prevent further damage. My next step is to pull an oil pressure reading, and see if the engine has adequate oil pressure. I just haven't been able to get it in the shop to do so. There isn't much diagnostic info out there on the actual injector pulse, and what helps generate it, or prohibit it other than the ECU, and we know that component is now good. Whatever happened while they had it was big, and the fact that we have 0 codes, but still a no start scenario is quite odd given the modern
is quite odd given the modern era of fuel injection, and it's array of sensors.Long and short: Yes fuel pressure, no injector pulse, no codes, no start.Everything functions as it should. If I had an odd warning indicator of any kind I would have a code stored. All lights that are supposed to come on do, and go out when they should. The only "odd" question is while cranking the oil light in the info center flashes after a few revolutions. Which leads me to my low oil pressure theory.Chat Conversation EndInitially we had no fuel pressure, and no injector pulse, and a myriad of other false codes due to their excessive back probing of the ECU. Now that we changed the ECU we have fuel pressure, and all the pumps energize, but we have no injector pulse. My concern is that when we crank it the oil light flashes. Some vehicles when experiencing low oil pressure will shut down the fuel injectors to prevent further damage. My next step is to pull an oil pressure reading, and see if the engine has adequate oil pressure. I just haven't been able to get it in the shop to do so. There isn't much diagnostic info out there on the actual injector pulse, and what helps generate it, or prohibit it other than the ECU, and we know that component is now good. Whatever happened while they had it was big, and the fact that we have 0 codes, but still a no start scenario is quite odd given the modern era of fuel injection, and it's array of sensors.
JA: It's good that it's giving you information about the problem. The VW Mechanic will know what to do. Are you hoping to fix this yourself? OK. To minimize me, please click the down arrow at the top right corner of this box.
Customer: Long and short: Yes fuel pressure, no injector pulse, no codes, no start.
JA: Is there anything else important you think the VW Mechanic should know about your VW?
Customer: Everything functions as it should. If I had an odd warning indicator of any kind I would have a code stored. All lights that are supposed to come on do, and go out when they should. The only "odd" question is while cranking the oil light in the info center flashes after a few revolutions. Which leads me to my low oil pressure theory.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the VW Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: VW
Expert:  Juan Crespo replied 1 year ago.
Hi there.JustAnswer is not a forum, instead it is a site where you can get answers to your automotive questions from verified professional experts. Hopefully having clarified that point, what is your question?
Customer: replied 1 year ago.
My question is in there
Customer: replied 1 year ago.
I have fuel pressure, no injector pulse, no codes and won't start. ECU has been changed out
Expert:  Juan Crespo replied 1 year ago.
Got it. Can you tell me what year, model, engine and transmission type is in your VW?
Customer: replied 1 year ago.
2009 Volkswagen Jetta TDI
Expert:  Juan Crespo replied 1 year ago.
Thank you for that information.The ECU provides injector pulse based on signals from the Engine Speed sensor. To diagnose, use the scan tool to check engine speed (RPM) while cranking. If no RPM or erratic reading, use two channel scope to check Cam and Engine Speed sensor signal strength and synchronicity. Depending on results, check sensor resistance (Engine Speed appx. 1540 Ohms - Cam 1.5 Ohms) and replace as necessary. If sensors OK but still no signal, check connectors and wiring between sensors and ECU and repair as necessary.Please let me know if you have any other questions regarding this issue.Best Regards.
Customer: replied 1 year ago.
RPM's are normal. Anything else? Im not getting any codes but still won't start. Fuel is going out like normal. Glow plug issue?,etc
Expert:  Juan Crespo replied 1 year ago.
Glow plugs are controlled by the ECU based on signals from the Engine Temperature sensor. Is your issue that the injectors won't open or that the glow plugs won't come on?We're looking for engine data, not just codes. Do you have access to a VCDM (first choice) or VAG-COM scan tool to properly diagnose this issue?
Customer: replied 1 year ago.
Not to be mean but I'd have to say this is a waste, I haven't learned anything new. Everything you said can be found in a VW Forum or online. I need to know stuff that VW doesn't tell normal people. I have no injector pulse. I'll never buy a VW again.
Expert:  Juan Crespo replied 1 year ago.
I'm sorry if you felt your expectations were not met. Regardless of what you might have heard or read, cars are complicated machines that require sophisticated equipment and tools in order to diagnose and repair them.Please understand that all I can do from where I am is offer you my technical knowledge and guidance. Also, please be aware that the guidance I offer is based on the same OEM instructions that are followed by dealer techs everywhere.It looks like you're looking for something other than what I have to offer, so I will opt out so others may try to help. Please do not reply until another expert responds or the site will cycle this back to me.