Bad ECU Connectors!! FYI

[cygnusx1]

Well, here is an update after over a year of smooth running with no issues. Some may remember the thread about the multi pin connectors on the L28ET fuel spark computers. Many people have posted about problems with misses and running rich and bogging under load...etc. Well I was out for a usual ride in my Z today and it was running great as it has been for over a year. About a year and a half ago after wrestling with the ECU connectors every two weeks I decided to use some dielectric grease on the AFM and ECU plugs. It worked great for all this time until now. All of a sudden, under load, anything past 1/2 throttle either the ignition or fuel was cutting out completely. I thought maybe my fuel pump was gone or maybe I was out of fuel. Luckily I was about 1/4 mile from where my parents live so I diverted towards their house. As I drove, the problem got worse and worse, I had to milk the gas pedal to get the car into their driveway. When I stopped in their driveway, it stalled. I cranked it over and it would NOT fire up at all. I pulled the coil wire and had my brother who happened to show up, hold the wire to a strut bolt while I cranked. No spark at all. I had fuel pressure, I had fuel pump, I had fuel, the relays for all the systems were clicking on and off. I disconnected/reconnected the AFM plug. That made no difference. I pulled the ECU off the kick panel and disconnected/reconnected all the multi-pin plugs. Cranked it over and it fired right up. Problem solved.

 

I'll say it again. 9 out of 10 problems with running conditions on the L28ET electronics are caused by those D#$& connectors.

[phil280zxt]

I know your frustration, though my 280zxt has never misbehaved as badly as yours did today, I have not had the trim piece that covers the ECU installed for the past two years. It's too the point that I wiggle the connectors before every outing. I think I might bite the bullet and splice in the set of 300zx connectors I have laying around!!

[EvilC]

Well' date=' here is an update after over a year of smooth running with no issues. Some may remember the thread about the multi pin connectors on the L28ET fuel spark computers. Many people have posted about problems with misses and running rich and bogging under load...etc. Well I was out for a usual ride in my Z today and it was running great as it has been for over a year. About a year and a half ago after wrestling with the ECU connectors every two weeks I decided to use some dielectric grease on the AFM and ECU plugs. It worked great for all this time until now. All of a sudden, under load, anything past 1/2 throttle either the ignition or fuel was cutting out completely. I thought maybe my fuel pump was gone or maybe I was out of fuel. Luckily I was about 1/4 mile from where my parents live so I diverted towards their house. As I drove, the problem got worse and worse, I had to milk the gas pedal to get the car into their driveway. When I stopped in their driveway, it stalled. I cranked it over and it would NOT fire up at all. I pulled the coil wire and had my brother who happened to show up, hold the wire to a strut bolt while I cranked. No spark at all. I had fuel pressure, I had fuel pump, I had fuel, the relays for all the systems were clicking on and off. I disconnected/reconnected the AFM plug. That made no difference. I pulled the ECU off the kick panel and disconnected/reconnected all the multi-pin plugs. Cranked it over and it fired right up. Problem solved.

 

I'll say it again. 9 out of 10 problems with running conditions on the L28ET electronics are caused by those D#$& connectors.[/quote']

 

Get a V8!!!!!!!!!

[cygnusx1]

Hmm let's see. Took me about $1500 to convert to an L28ET with a TO4B and an good intercooler, fuel pump, and FMU, with A/C. Result 265RWHP/300RWTQ that drives like a factory vehicle. It was basically a direct bolt in with minor fabrication. The electronics basically transferred right over. Asides from electrical connectors loosening there have been NO issues.

 

How much is a V8 conversion going to cost per horsepower? How much labor invlolved?

 

Right now I am enjoying driving the car. Someday when I feel motivated, I'll go V8 or maybe I'll save that for a Cobra.

[Metallicar]

I am not ready to do the swap yet, but I am close. I have been reading all of the swap related posts looking for problems guys have had before and after their swap.

 

This bad connector problem seems to be prevelant. Even after cleaning the connectors and exersizing them in and out, they fail.

 

But, I am wondering, is that really the issue? Could it be that the ECU, needs to be reset? Would disconnecting the Battery and reconnecting it provide a required reset? I don't know, is there an eprom or something that needs a reboot?

[phil280zxt]

The ECU's in the 280ZX's are not that advanced. No eprom, reset or reboot options. I've been told of two fixes, one is to carefully bend each of the pins a little so they grip better, the other is to replace the original plugs with those from an 86 or newer 300ZX. They are identical and seem to fit much tighter.

[Tony D]

I am not ready to do the swap yet' date=' but I am close. I have been reading all of the swap related posts looking for problems guys have had before and after their swap.

 

This bad connector problem seems to be prevelant. Even after cleaning the connectors and exersizing them in and out, they fail.

 

But, I am wondering, [i']is that really the issue?[/i] Could it be that the ECU, needs to be reset? Would disconnecting the Battery and reconnecting it provide a required reset? I don't know, is there an eprom or something that needs a reboot?

 

 

NO! They are "dumb" there is no "learning" like on the newer ECU's.

 

They are now (at the best) 23 years old. Put a tin can out in a room, and let it sit for 23 years, and see if that tin is still nice, shiny, and bright after 23 years. Think about it.

 

Don't make it sound like it's all that out of the ordinary for a car with 23 year old components to have issues with electrics. The thing to take away from Cygnus' Post (IMO) is that by insulating the pins properly with Dielectric Grease, and keeping OXYGEN away from the freshly cleaned plugs the RAPID REOXIDATION is forestalled for a much longer period of time.

 

I have gone through this myself, and learned LONG ago that Dielectric on EVERY Low-Voltage contact in the EFI system was THE way to do it.

 

Something about cleaning the connectors mechanically or chemically seems to leave them open for rapid reoxidation.

 

I have recently begun using the DEOXIT product from Radio Shack, but even after "gold coating" the pins, I STILL am using dielectric on the parts. I think the second part of the Deoxit product is simply another method for preventing reoxidation.

 

If you look at the newer connectors, the OEM's have taken GREAT pains to seal out moisture form the pins, and make the connector virtually airtight at the same time. Nice multi ribbed silicone barbs sheathing the pins individually, going together so tightly they "pop" when you break the suction pulling them apart. OEM's realized low voltage doesn't like corrosion (resistance), and now have figured out better connectors to keep the contact clean.

 

Short of replacing the connectors with modern types, the only other reasonable alternative is the dielectric sealing of the pins.

 

There IS a secondary failure mode whereby the wire at the end of the loom corrodes and causes problems, but that is more in the engine compartment, and not at the ECU multi-connector. That is solved with replacing the connectors and using proper pigtails or harness repair techniques.