Most liked posts in thread: GNAT - Rebuild - The Sequel

The injectors were sent to RMW with the head for bench testing, as well as balancing, that's not to say there isn't a temperature dependent short occurring. I will be doing some more testing this afternoon and may come to the point of replacing the rebuilt 550s with a set of new in the box 550s and pigtails.

My name is Nick Fry, I am the technician at Detroit Tuned. I am 24 years old. I graduated from the University of Northwestern Ohio in 2011 with an Associates in Applied Sciences with a major in Diesel Technology, minors in automotive repair.

I have a dog who can clear a room with one fart, and ruin a nights attire by simply putting her face near anything dark colored.

My tool box has more granite on it than most suburban homes in the area, and has yet to truly earn its name of "the sushi preparation station."

Just the short intro.

 

We have been putting tons of hours into Nates car to make sure it was done for the delivery. Once we had it started and running we started the tuning with RMW for his stand alone ECU. From time to time we would get a no start condition and we would do a few things then it would start.. So okay, lets tune.

One day during the tuning it would cut in and and out, so we tried a bunch of items to keep this from happening. Basically it is getting low spark, but no codes. So after thinking it was part of the RacePak that was in his car that was giving us a different screen every time we drove the car, we spent all day Tuesday taking things apart to find and fix any electrical issue we could find to make sure it was tuned and ready to go. that way if Tuesday didn't fix it, we still had Wednesday and Thursday if we needed. We took the RacePak out that was half installed and had pinched wires in several places. After the RacePak was removed the car fired right up, and was not giving us the cut out it was before, and all looked good. We started the car several times during the tuning process, as well as at different times and heats. No problems. Awesome, the car is working the way it should, the tune looks good and is starting every time. Looks like we solved it.

OK Nate it's ready to go, and your mirrors work now and a bunch of other things are fixed. On to the next project...

Washed the car so he could see out the windows for the drive home.. Pulled it in... No problems.

Preparing for delivery the next morning...Come in to pull it out..No start..Crap..But why.. Spent another 6 hours on it with testing, new sensors, and even a known working engine harness. Something is telling the car not to start. No spark delivery at all... So it's back to the drawing board to figure out what is happening in this car. We have ruled out several things but just ran out of time to make sure he had a reliable car to drive 4 hours home. We will get back on it and try to figure it out and get it back to him as soon as we can so we can get other projects done as everyone is waiting on cars. more to come... Chad

 

To reiterate the amount of time we have into Nates car.

1: Car was trailered back to our shop following Dragon this year.

2: Head was pulled to find that a chunk of cast was missing from the valve seat/combustion chamber of cylinder 2.

3: After the head was pulled the head and injectors were sent to RMW for repair, rebuilding and injector flow testing.

4: While the car was waiting on the return of the head and injectors we repaired multiple broken harness connectors, whether it was as simple as the red retention clip missing, or the connector itself not being able to clip onto sensors. We ran a new boost reference line, as well as tucked the wiring to multiple components to be more appealing on the eyes.

5: We at one point had to pull the rear brakes apart to clean and lube them, as the TyrolSport pins had become sticky and caused the rear calipers to hang, causing the simple task of pushing the car from one end of the shop to the other to be a 2 person job with a wheel dolly.

6: The RMW components were returned to us and Nates car was promptly scheduled to be put back together.

7: We assembled the car to find out that compression was low across the board, and turns out there was a mishap while the head was being refinished and the valves were not sealing properly. The head came back off, went to a local shop where the valves were fixed and the head was reinstalled. At which point the car had not had any tuning work done to it, the car was started for a few seconds to verify that it would start.

8: Somewhere between us getting the car running and now an electronic gremlin decided to rear its head. We began the tuning process with Jan and the car was hit and miss. It went for days starting fine, no issues then the following day it wasn't even getting spark. We would get it started, proceed to tune the car, all the while the car ran fine, but the final tune we did with Jan he verified that the car was safe to drive and may require marginal changes as things break in and the car is driven more regularly.

9: Gnats delivery.. The car was running strong the day before with zero issues being present, I even had a joking demeanor when I went to start the car and pull it out. It started and ran on 2 cylinders, so I shut it off and proceeded to attempt to restart it only to find out that it was back to a state of not getting a trigger signal.

10: We then spent the rest of the day that Thursday trying to diagnose why the car wasn't getting a trigger voltage to either the injectors or coil.

10a: We began backprobing the crank sensor and cam sensors to analyze if we were getting proper voltages from them, as they are where the car gets trigger signals from to collapse the coil and fire the cylinder. Voltages checked out. The EWS was providing 12V at pin 10 on the 40 pin DME connector, but Jan also said that the ViPec nullifies the EWS immobilizer feature, so essentially it takes the cars anti theft to that of a late 90's Chrysler.

10b: The car still didn't want to start; fuel pressure checked out at over 55 PSI cranking pressure. We had intermittent spark, with no fuel being injected. We tried to trial substitute a factory DME and start the car to still see we had no trigger voltage, so we then replaced the harness with a known working harness. To no avail.

10c: We made sure all the major grounds were making contact with the chassis in order to provide proper ground.

Today: 9/14/15

10d: I again trial substituted a factory DME into the car, but this time with the intentions of using it as a diagnostic port. I cleared the codes and cranked the car for 15 seconds, at which point I rechecked the fault codes and came back with a P0340 cam code. I cleared it and retried the cranking sequence and again got the P0340 cam code, so I replaced the cam sensor with another known working sensor. Retried the crank sequence with no recurring cam code.

10e: With the reasonable things checked and easy bases covered, injector #3 was unplugged first (no real reason why) and a 194 bulb was made to work as a makeshift noid light. THE CAR STARTED. Cylinder 3 injector was unplugged, the car fired right up and ran on 3 cylinders. The injector pigtails were checked for shorts and continuity and seemed to check out. I left the pigtails connected to the injectors and tested resistance on all 4, all of which came out to approximately .011K Ohms.

I left the shop at just before 8 PM EST tonight and the car physically started and ran on its own. What the reason was, I don't know truthfully. I intend on doing some more testing tomorrow, which may include doing some temperature dependent testing on injectors, there may be a temperature based short in one or more injectors causing starting issues.

Nate: We appreciate your standing up and understanding the massive amount of work and man hours that have gone into trying to deliver a reliably running car. We are as disappointed as you were to make the long drive home and it not be in Gnat, every spare second we have is dedicated to finding a solution to the ongoing wait you're enduring. This has been a long drawn out unfortunate turn of events, and when we are able to finally deliver your car it will be the utmost of quality that we strive to deliver to each and every one of our customers. The scale of this job has grown to levels that nobody expected, we have consulted multiple entities from friends that work in the automotive field to competing vendor techs, as well as multiple phone conversations with Jan, and everyone we've talked to has agreed with the trajectory we took, even shocked to find out the depths we've gone to to make this car run.

 

Lemme tell ya, I'm sure my neighbors will be having a party that I'm not invited to now that Gnat is gone. :lol:

With everything that has gone into this, lets try to keep it running for at least two years Nate. :fingerscrossed::wink:

 

Since the car starting on Monday it has continued to start and run on its own accord each day following, and today I put around 10 miles on the car with no hiccups.

Prior to taking it out I again Ohm'd out the injectors, pigtails, as well as tugged on pigtails and moved them around while testing.

Pigtails Ohm'd out at 0 Ohms.

Injectors Ohm'd out at 12.1-12.2 Ohms (normal operating range), with no issues to be found.

Finally, Gnat's original wiring harness was reinstalled, as it was cleaner looking than our test harness. Everything that has been done today was done in steps and once each test was completed, or each component was unplugged/plugged the car was started to verify no faults.

I plan to daily Gnat for the next few weeks on days that are deemed fit, in the hopes that we can have at least 250-500 miles on the car prior to delivery to wait out any unsuspected quirks that may pop up. :fingerscrossed:

 

I am just in for carnage pictures.

 

Gnat made his first of many visits to my neck of the woods, no issues, cruised right along on the freeway.

Now has a cumulative 25 miles on him.

More to come as the days go by. :cornut:

 

What?...

 

When a Mommy block and a Daddy cylinder head love each other very much....

I am so not going to finish this.

 

So true....
I did get to play with the Gnat today

 

Nate is Jewish, or used to be, so the Jesus head is out. To be politically correct, Jan would have to build him a Moses head.

 

You guys are making my head hurt. I miss the days when I could whack a carburetor with a hammer to get the engine running again. :sad: