dfinnegan

I've read in Streather on page 387 that you can test the DME relay by doing the following:

"Install a home-made jumper lead set across connectors 3, 5 and 7 in relay socket. (These pins correspond to pins 30, 87 and 87b on relay.) This jumper set up distributes power directly to the DME and fuel pump."

Does this mean that I create a wire with three leads all connected as one y-shaped wire and then plug these three wires directly into the appropriate slots on the fuse panel?

I'd like to perform this test and want to be sure that I'm doing the correct procedure.

Thanks,
Dave

Red rooster

Yes , thats the one. Dont forget to use some reasonable wire as there are a few amps involved !
Good luck
Geoff

Indycam

Hiya dfinnegan
Be very carefull , the beter test is to put in your other dme relay .
You do have another , don't you ?

Dunasso

In a backhanded kinda way, Indycam makes a good point. If you don't have an extra DME Relay you should get a spare one for the glove compartment. You never know when the current relay is going to take a ****. And with the spare, you won't be stranded.
On the other hand, the jumper wire set up will limp you along until it can be replaced. It's also cheaper and less suseptable to damage while being thrashed around in the car. You know how harsh those high G chicanes and skid-pad tests can be.

Duncan

dfinnegan

Actually, I do have a spare relay and I've tried it to no avail.

It's just that of the eight symptoms described by Streather on page 387 I have three, for sure, and perhaps another two. That's possibly five of eight which suggests that I may be unfortunate enough to have both a bad DME and a bad spare DME.

I know I'm grasping here, but I've been two weeks without my car and am getting rather desperate to determine what's wrong with it!

Here are my symptoms:

1) Cold start is fine. Idles around 900rpm. It hunts a bit, but less than 100rpm either way.

2) After a couple of minutes it stalls. I restart and it stalls immediately. I can only keep it going with my foot on the gas pedal.

3) Driving seems fine up to 3k rpm, or so. No jack rabbit starts as I'm testing and am quite nervouse about how she's running so I can't speak to the acceleration below 3k.

4) Nearing 4k rpm, and absolutely beyond 4k, there is no acceleration. In fact, putting my foot down on the accelerator causes hesitation and serious lack of power. If I "nurse" it up to 4k rpm she'll run there and even higher, but, again, putting the pedal down to any real extent causes hesitation and serious loss of power.

Streather indicates symptoms of a bad DME could include any of the following:

1) Fuel pump not running when ignition turned on (nope; I'm fine)

2) Engine losing power at around 4000 rpm (yes!)

3) Power stalls, sudden loss of power (stalled at speed once)

4) Intermittent hisitation problems (yes; more serious w/ higher rpm)

5) Fluctuating idle rpm (yes when cold; no idel after 2 mins)

6) Engine will not start (starter motor cranking correctly) (nope; I'm fine)

7) Fuel can be smelt whilst driving (don't think so)

8) Engine management system stuck in open loop mode (maybe; I don't know enough to be able to tell)

It feels like I must be in limp-home mode. Is this the same thing as stuck in open-loop?

What I've tried:
1) cleaned intake and isv (only got worse)

2) new oxygen sensor - had trouble getting it installed due to old threads remaining behind. Finally in. Same, same.

3) probed cylinder head sensor at DME connector and I think it's fine.

I would really like to get to the bottom of this.

If anyone has any thoughts, suggestions or comments of any kind . . . please!

Dave

dfinnegan

Oh, and another thing that may be useful information . . . when I arrived home from my last test drive and turned it around in the drive to get it in the garage my wife told me that there were flames coming out of the tail pipe!!

Indycam

Hiya dfinnegan
Running real rich or bad spark causes flames out the tailpipe .
It sounds like you might have bad spark .
I'd look at ignition parts . Have you ?

Its very unlikely you have two bad dme relays ,
and that they are bad in the same way .
So I would look away from the relay .

dfinnegan

I haven't looked at the ignition parts yet. I have been thinking (perhaps wrongly) that ignition problems would be consistent - hot vs cold, low rpm vs high.

Am I being muddle headed?

Also, what should I be looking for?

Thanks,
Dave

dfinnegan

A bit of clarification on the flames . . . my wife tells me that the flames were seen when I restarted the engine (I stalled turning around) and not while I was just running.

Indycam

Hiya dfinnegan
"Am I being muddle headed?"
Wecome to the club , I'll like any nice muddle head .

"Also, what should I be looking for?"
Ah , well , gee ,
Have you ever had the ignition parts apart ?
Have you had a look see inside the caps ?
How do the rotors look ?
Hows the tops of your coils looking ?

Indy muddle cam
Muddling along from 1960

dfinnegan

I've not yet pulled the caps or mucked around with the ignition wires. I'll take a look at that tomorrow.

I'm new to this sort of thing so I'm not sure I'll konw a problem if I see it.

Can you give some idea what to look for? Should I be looking for burnt rotors, loose wires, cracking, . . . ?

Thanks,
Dave

dfinnegan

So here's another thought. Just before I started having problems the car was worked on by a specialist. They did an engine clean with some sort of orange smelling cleaner. Might it be possible that some ignition bits were compromised during the cleaning process?

Dave

Indycam

"Should I be looking for burnt rotors, loose wires, cracking"
Yes . And burnt cap / caps , tracking on cap / caps inside and or outside .
Toasty / tracky coils , leaky coils .
Old wires that leak spark . Start up the motor in the dark of night , not inside , outside so as not to gas yourself , and have a looksee for sparks from old broken down ignition wires .

Do you have a digi camera ? If so take a pic of the wires on the cap before you pull them , make good notes as to how they go back on , with 12 wires going to two caps it gets to be a real mess quick if ya don't , draw a guide for yourself before pulling one wire off . Trust me it worth the time upfront . When you pull the cap be very carefull , its easy to scratch the inside of the cap on the rotor tip . Take all the wires off of the cap and then undo the screws , pull away the cap slowly .

Indycam

"Might it be possible that some ignition bits were compromised during the cleaning process?"
Yes and other parts as well .

dfinnegan

I do have a digi camera and will take some pics. For me, and to post.

Just to be clear, the symptoms that I'm having could be caused by problems with the cap, rotors, wires and othe ignition parts?

Thanks so much,
Dave