Help with my del sol, I'm lost!
 

Alright so I've thrown aprx. 6 different ICM's at my del sol with an LS swap. At a minimum 2 were working just fine...However every time I change one out the tach problem doesn't present itself in the same manner..Whether the engine is hot or cold...And I'm beyond lost.

Here's a video of what it's doing http://www.youtube.com/watch?v=wzk3EKmjOp8 As you can hear the engine speed stays the same and there's no way a honda would be capable of changing engine speeds that quickly anyways.

At the moment I am running a hondata s300 with the stock loaded p74 map, which I have 'put' to the ecu a couple times already with out making any adjustments. I'm not sure if that is for some reason giving me the problem. My other thought is the main fuel relay because not shown in the video the car does miss fire really bad, and the main fuel relay has been giving me issues for a few years now when ever it's humid outside..Or could it still be the ICM..

I have also tried hooking up an obd-1 PR4 ls ecu and no dice with turning on the fuel pump or anything for that matter, then as soon as I plug the s300 back in it starts.

Re: Help with my del sol, I'm lost!
 

speed sensor cheange it...

Re: Help with my del sol, I'm lost!
 

doesnt the speed sensor only affect the speedometer? While the Tachometer gets it's input signal from the distributor?

Re: Help with my del sol, I'm lost!
 

check the ground wires. i had the same problem and it was a ground wire. if its not a ground wire try the speed sensor. if the speed sensor is messed up it may affect the tach.

Re: Help with my del sol, I'm lost!
 

The speed sensor supplies the speedo signal not the tach signal.

Start by resoldering the main relay. Click here.

Is the ground on the thermostat housing clean and tight?

Is it possible that the tach itself is bad? If you had an OBDII system, Id' say hook up a scan tool to see whether the engine rpm reading also jumped around there. Anyone have a cluster that they would let you swap in?

Re: Help with my del sol, I'm lost!
 

Yeah a new main relay all together will be in the works either tomorrow or monday They're not that much.

It's obd-1, and i've data logged it with smanager and the idle/rev's stay constant where they should be with throttle position. And I guess i'll give a different cluster a shot if it works that'd be great. I actually have a spare si del sol one that was working on a parts sol I had parted out a few years back.

However, none of these issues happened when I had the boosted z6 in there. Just came about once I installed the LS.

You can't tell in the video, but I also get massive miss fires from time to time, and the timing is dead on. Like the car runs mint until it gets to operating temp and then starts to act up.

Re: Help with my del sol, I'm lost!
 

Re: Help with my del sol, I'm lost!
 

Yeah I posted that I was gonna get a new one prior to seeing that link. I knew I could solder it, but just always thought a new one would be best. It's had those symptoms since I had the original d15b7 in there which was 3-4 years ago now.

Good point as to where the ecu is getting the rpm signal from. I'm not sure where the hondata s300 get's it's input from. I'll have to readdress the Thermostat housing again with a wire brush to confirm that it's cleaned up. and swap out the coil for a different one I have kicking around.

As well as inspect the blue tach signal wire again. what do you think the likely hood is that there could be a break underneath the shrink wrap/oem casing that is put over the wires?

And zero CEL's. the light does work too.

Re: Help with my del sol, I'm lost!
 

It's feasible. Resistance/Ohm testing the wire with a multimeter should tell whether it has a break or short.

Re: Help with my del sol, I'm lost!
 

Well taking the advice of here and a few other forums, I started off by cleaning the thermostat housing ground surface really good, down to shiny aluminum. As well as added a 4AWG ground to the thermostat. I also got a new battery and some new NGK spark plugs.

The car runs mint now!

Also for shits and giggles I tried plugging in the obd-1 PR4 again to see if it would start the car up(which it wouldn't before) so I wouldn't have to keep the S300 in it and she started right up!

However the one issue with running the OBD-1 PR4 ecu is the case does not have the same mounting design as lets say a PO6 or P28. So in order to properly mount the PR4 I removed the entire board and installed it into a PO6 I had kicking around. It fit perfectly and worked great. I love how universal hondas are!!

**EDIT: Oh and I also got a new main fuel relay from the junk yard with no cold solder joints. I attempted to re-solder it myself but it's above my soldering iron and my skill level.