Strange problem

[Tom944]

In the morning my 87 NA idles more like an old V8 and goes chuff chuff as I pull away. This improves throughout the day until it runs ok in the evening, although the idle is still a little shakey. The car spends most of the day parked, I drive it a couple of times for after miles. I did have a loss of power but a new coil solved that.

The car is parked in the sun, so it could be the heat of the sun that helps not the engine heating up!

Hard to trouble shoot since it runs better in the evening.

Most ignition and maintenance parts are new. It's garaged at night.

TPS and wires tests fine. Unplugged it though to see if it runs better in the morning. Some times it smells a bit of gas. Plugs look fine. Injectors sound fine.

Very confused!

[v2rocket_aka944]

How old is the O2 sensor?

[Tom944]

O2 sensor is a year old. Unplugged it and did not get any profound improvement.

To me it sounds like moisture condensing somewhere but I pulled all the HT stuff apart and checked it. Its all about a year old. I listens to the injectors with a stethoscope and they all sound the same.

[Tom944]

Another point I should mention is that this started when I uncovered the car after its winter hibernation. I did idle it a few times over the winter.

[mytrplseven]

I'd suspect you have fuel issues. If you stored it without a fuel stabilizer, you may have varnish in the injectors, fuel filter or the fuel itself. The only way to deal with this is to drain all the gas, pull the injectors and send them to Witch Hunter in Duvall, WA for a $100 rebuild and replace the fuel filter.

[Tom944]

Good suggestion. I did use stabilizer. The injectors were serviced by Whitchhunter last year. I am running Seafoam in the gas at the moment. This could still be the problem. Not sure how to confirm this.

[Rasta Monsta]

Worn AFM?

[Bukowski]

Not to boast, but

I had a no-start problem. I bought a can of SeaFoam but resisted the urge to pour it in. After resealing/rebasketing/cleaning the injectors, replacing rotor+distributor, pumping all the old gas out, putting a few gal fresh gas in, running the pump jumpered, AND THEN PUMPING THAT gas out THROUGH THE FUEL RAIL FITTING (thanks to user BoxsterGT for the handy hose for both this and for pressure testing!), and THEN adding fresh gas and circulating that by jumpering the fuel pump (the standard 87b thingy), running the starter with the spark plugs out and fuel injectors disconnected,... where am I - is anyone reading still?... put it all back, and oh how sweet it was to hear it run. No cans of SeaFoam were harmed in the solving of this no-start problem.

Of course, many of those steps might have been irrelevant, but it's what I did.

In retrospect, and for this case, I wonder what a simple purging of the gas as I described above could accomplish by itself. In my case, fuel injectors were in fact bad though....

[John_AZ]

OP, A couple of months ago my '87 would start, run fine, enter roadway and then do an intermittent second or two shut down- -------then run fine for many miles and then shut down for a second or two again.

I did the replacement of new Bosch wires, plugs. drain gas, new fuel filter, grounds and....

The solution was a replacement DME computer. (my spare)

Maybe the issue you have of "loss of power" could be the same.

GL
J_AZ

[mytrplseven]

John's right about that possibility. The soldered lands and circuit paths on the old DME's are known failure items due to cold joints. It's a pain but disassembling the DME and resoldering (carefully) any suspect connections on the boards is worth considering. Or, simply buy a known good replacement or have yours rebuilt.

[Tom944]

I replaced the plugs for the hell of it. Inspecting the old ones it looks like one is blacker. Current theory is that that injector is leaking in the morning and getting better as the day goes on. Symptoms are generally improving since seafoam. I will get the injectors cleaned again if it dies not improve. Away today and will look at it again tomorrow.

Thanks again for all the help.

[Tom944]

Here are a couple of pictures of the plugs. The one on the left is from the front most cylinder.

[Tom944]

I pulled that injector, very easy since they have recently been refurbed at Witchhunter. Played with some throttle body cleaner and a paper cup for a while and then walked the dogs (not sure if this is a critical step or not). Put the injector back in and it runs great!

Not sure if I have cured it or if it's just messing with me again! Certainly was a night and day difference but I've thought that before only to have it run badly in the morning.

At least it keeps me out of my wife's way on a Sunday morning.

[Tom944]

The issue did return but less often. I ordered a remanufactured injector from our host. Hopefully that will cure it. I can still smell gas and get the occasional pop from the exhaust so I am still assuming that it is the injector. That plug looks like its fuel fouled or rich to me. Once I put the replacement in I will send the old one to Witchhunter.

[Rasta Monsta]

There is a German word for that #1 plug...ge*****t.

Sent from my Nexus 6P using Tapatalk

[Tom944]

I have had many words (mostly not German) with the car recently. If the injector foes not fix it I will probably try an exorcism. Would that need to be conducted in German?

[Tom944]

The remanufactured fuel injector appears to have fixed the problem. Between that and the new coil its running better than ever now.