1G DSM, get it up and running thread.

[HunterDG]

******The problems described in this first post have been solved, see subsequent posts for update..******

I've got a 1G DSM with some issues.. I'll try to describe as best I can.. hopefully someone can help me get this sucker started.

I've been told the car ran fine before being parked..

When i turn the key to 'start' the engine does not turn over.
If i short the starter signal connector straight to the battery, the engine turns over.
The stock black starter signal wire seems to be fine, not chewed. There is no evidence that any interior harnesses have been chewed through, and the clutch safety switch seems to be in good shape.

I replaced the spark plug wires, and the engine WILL start and RUN for several seconds if coaxed with a bit of carb cleaner in the intake mani. I'm assuming this means the ECU is good, but i have not checked it

when the ignition switch is in the ON position, i hear a clicking coming from near the throttle body.. i assume this is the ISC motor?

when cranking the motor (by shorting the starter signal to the battery, I can smell fuel, but cannot find any fuel line leaks, and the engine does not start.

The FPR vacuum line is chewed through, and open to atmo.. would this make the engine not even start & idle?

The harnesses on the drivers side firewall are all chewed through..

I've attached some pics..

any suggestions? My main concern is to just get the car running/idling on it's own. I'll fix the rest later.

 

Your ECU could be bad, especially if you hear the ISC clicking. A shorted ISC can burn out components in the ECU. Pull the ECU out, open the cover, and unscrew the board from the case. Look on both sides for anything that looks burnt. Look at the capacitors to see if any have leaked onto the board. And smell it. Bad caps will smell like rotten seafood, even if you don't see anything leaking yet. I've had bad ECU's that let the car start, run a few seconds, then die. I've even had one that let me drive down the road, die, restart, and drive more before dying again.

Whether or not the ECU is bad, also test the ISC with an ohm meter. If the ISC is bad, replace it so it doesn't ruin your ECU or any new ECU you install.

With that much wiring and hoses chewed, and maybe even more you can't yet see, its going to be quite a chore to track down the problem, but I would start by making sure that the ECU is 100% known good. Then you can use a logger or scan tool to check for codes in the ECU which may help you narrow the search.

 

[tommyp]

Gotta get to the root cause. Google for "swimming pool of death" /ubbthreads/images/graemlins/wink.gif

 

[HunterDG]

Well, the fuel pump was to blame.. completely rusted..
cleaned out the tank and replaced the pump with a walbro 255, and now the car starts, but will only run for ~30 seconds..

I don't have a logger right this moment, and will probably have to make a cable this weekend.. anyone have any suggestions in the meantime?
seems like i've read about this problem somewhere..

 

[jepherz]

Unplug the maf and see if it runs longer. Maybe the maf is broken and outputting values WAY off. Unplugging the maf will make it run, albeit very rough.

 

[slugsgomoo]

+1 I had that issue. Car ran fine when parked, and when i went to start it like 4 months later my 2g maf had taken a crap. /ubbthreads/images/graemlins/rofl.gif

 

[HunterDG]

Quoting jepherz:
Unplug the maf and see if it runs longer. Maybe the maf is broken and outputting values WAY off. Unplugging the maf will make it run, albeit very rough.



Will do when I get home!

Happy B-Day!

 

[HunterDG]

Quoting dsm_drew:
Your ECU could be bad, especially if you hear the ISC clicking....



sorry, I totally missed this post..

I took the ECU out, and to be perfectly honest, it looks FLAWLESS! I'll post pictures on request, if that will help to be sure, but everything looks to be in great condition.. no bad smells, nothing burnt (my VR4 ecu was burnt and had a toasted ISC driver, so, for the most part, i know what it would look like)
keep in mind this car has probably been sitting for 1/3 of it's life, or more, so fewer heat cycles to pop anything on the ECU..

the ISC motor does click, but for troubleshooting purposes, I've just unplugged the connector. Unplugging it has had no effect on the ~30sec run time.

As far as logging the ecu, I'm having a bit of trouble with that.. see this post: Topic: TMO Logger 'working properly' but 'link is down'.. suggs?

 

[HunterDG]

Quoting HunterDG:
Quoting jepherz:
Unplug the maf and see if it runs longer. Maybe the maf is broken and outputting values WAY off. Unplugging the maf will make it run, albeit very rough.



Will do when I get home!

Happy B-Day!



unfortunately, unplugging the MAF had no effect /ubbthreads/images/graemlins/crazy.gif

p.s. never pick your nose after eating hot & spicy cajun style snack mix!

 

[HunterDG]

is there any way to pull codes from the ECU WITHOUT a logger? (like honda/nissan which, when put in diag mode, flash the CE light to 'spell out' error codes)

 

How well did you clean out the tank. I had to hot tank and reseal the gas tank on my 3000gt after sitting for five years. I cleaned it out prior to this but light surface rust was clogging the strainer and heating up the pump. It would drive for a couple of minutes and then start to stutter before dying. It would idle for almost 30 minutes before it would start to die.

 

Here is how you can read the cel code without a logger. Old school but still works.

buzzer

 

[Wizardawd]

You can also use any multimeter. An analog one works best for this, the cheap $10 ones work just fine. A digital can be used as well, just set the range setting for 2000mV instead of 20V.

Then, it's just a matter of watching the sweeps and pauses. The codes will constantly repeat themselves so if you get the same code over and over that's all there is.

Example: long pulse, long pulse, short pause, short pulse = Code 21 (ECT sensor)

Wiz

 

[sydrew]

very good keoni that how i pulled mines too but wow that was very good of u to do step by step and the codes

 

[HunterDG]

Quoting keoni176:
Here is how you can read the cel code without a logger. Old school but still works.

buzzer



Keoni, and Wizardawd, thanks very much for the info.. i'm a bit ashamed to say I missed that article on the vfaq.. /ubbthreads/images/graemlins/frown.gif

anyway.. i ended up hooking up a little car alarm siren I had lying around, and got the codes, It was a little hard to detect the pauses between the short pulses with my digital multimeter..

It was throwing codes 12 and 44 (MAS and Ignition Coil/PTU) so I plugged the MAS back in and grabbed the coils from my galant - had to splice in the three prong connector and thus lost the tach signal (oh well)

BUT, now the siren sounds continuous short bursts, so that means everything is A-O-K

EXCEPT, the engine STILL only runs for ~30 seconds after I let go of the key from the 'start' position. (car will run continuously if I keep the key turned)

I'm pretty sure I hear a relay under the glovebox click about 1 second before the car dies. I thought it was the fuel pump relay, but ruled that out by turning the pump on with the test connector under the hood. Car still dies. anybody have any idea before I go relay-hunting?

THANKS very much for all the help thusfar!

 

[tommyp]

I had a similar prob with my gvr4 and I was chasing my tail for 2 week. The car would stay running for a second or two, the fuel pump relay would click and it would stall. There weren't any ECU codes and the datalogger said all was AOK. It ended up being the ECU. After repairing the messed up traces in the ECU, all worked fine. If you have a friend who has a dsm, see if you can borrow his ecu to test.

 

[HunterDG]

I'd love to use my VR4 ecu to test...

Maybe someone (keydiver?) can comment:

when using a 91+ ecu in a 90, can I just swap pins 6 & 14, and keep the 90 PTU or must I upgrade to a 91+ PTU as well? (is the PTU rewiring JUST for the TACH signal, or is it necssary for the ECU to run the car properly?) I guess I could figure that out if I look at the wiring diagrams... but I'd feel much more confident with a more-knowledgeable person's input..

I'd be willing to try with my galant ECU if I don't HAVE to rewire/replace the PTU with a 91+ model for the car to run right.

splicing the 91+ coil pack and reversing the plug wires was annoying enough (although fairly simple)

 

The tach will go crazy, but it won't affect the way the car runs. If you disconnect the wire to pin #109 while you are at it the tach will behave also. The only downside will be that you will never get a code #44 if there is a misfire.

 

[HunterDG]

Quoting keydiver:
The tach will go crazy, but it won't affect the way the car runs. If you disconnect the wire to pin #109 while you are at it the tach will behave also. The only downside will be that you will never get a code #44 if there is a misfire.



Thanks a bunch! swapped the pins and threw it in.. problem solved! that's both good and bad /ubbthreads/images/graemlins/smile.gif /ubbthreads/images/graemlins/frown.gif

the car is only running on #1 & #4 though, but I haven't checked spark plugs so i'm crossing my fingers on that.. hopefully it's nothing to do with the fact that I'm running 91+ coils on a 90 PTU. Someone correct me if I'm wrong.. when I spliced the 91+ coil in, the plug wire locations seemed to do a switch-a-roo on me. So now I've got the plug wires hooked up differently than the service manual shows..

The sad part.. I opened up the 'immaculate' 90 ECU to find that I had missed corrosion around at least ONE of the caps...
so.. Terry P, if you are reading this, let me know If i can ship this one off to you for diagnosis as well!

I'll have a camera worthy of taking closeups on tues, and I'll try to post up some pics of the ECU.

p.s., the galant ECU is throwing code 14 now, TPS, but the car runs like crap with it disconnected, and great with it connected, so I know it's got to be halfway-working.. I guess I can take it off and check it with a mutimeter to see if it is in-spec right? I think I saw that in the vfaq somewhere..


EDIT: I've got a 91+ ptu (and the 91+ coil pack)..

would it be in my best interest to go ahead and convert the car over to 91+ everything (ECU/coil packs/PTU)?

I've got a couple links to how-to's..
this one: http://www.ecanfix.com/users/mdhamilton/ecuconversion.html

says that I need to replace the gauge cluster as well..
I call BS..

From what i've read, i've discovered that both the ECU AND the 90 tach pull the RPM info from the noise filter on the firewall:

IS the signal output by the 1990 dedicated tach pulse thing DIFFERENT than the signal output by the 1991+ PTU?

It looks like I could connect the white tech pulse wire in my 90 harness (pin 109) directly to the white wire on a 91+ PTU, remove the noise filter on the firewall, and a 91+ ecu would read it fine, because that's the way a 91+ harness would work.

How would the 90 tach fare if I just spliced it in without the noise filter?

 

[HunterDG]

Sorry, I seem to have forgotten that this is a VR4 forum.. haha.. just realized how much of an ass I must look like asking about this stuff on here.. /ubbthreads/images/graemlins/smile.gif

I'll post up on a DSM forum and see what I can find.