ECM?

[GerryO]

OK, so my 1993 J30 has been running really great, until this morning.

It started easily enough, but idlled/ran very rough and the Check Engine light was ON - no blinking codes - just ON constantly, so I didn't even back the car out of the driveway and into the street.

I got gas a Shell station yesterday on the way home from work, so I cleaned-up and re-tightened the gas cap to produce no immediate improvements.

So I disconnected the battery and removed the ECM and the cover from one side - all was bone dry outside and inside and looked good - zero signs of corrosion.

I re-assembled and re-installed the thing to check codes in modes I and II. Mode I shows just the Check Engine light and the red LED ON constantly. Mode II is ZERO from either light at all. No flashing at all.

I disconnected the camshaft/cranshaft position sensor and the engine just cranked and would not start at all. Re-connected and the engine starts, idles rough and with the Check Engine and ECM LED lights still ON.

It's getting dark, so I figure I'll drive it around the block before parking it and coming back to it tomorrow. It starts and runs perfectly, and the Check Engine light is now OFF.

I pull into the driveway and bang on side of the ECM a bit and the engine shuts OFF. I restart the engine and it's still running fine and showing no codes, and bang on the thing again, but this time nothing happens. That's good.

Tomorrow I'll check for any leads on the circuit board that might be able to contact the cover and maybe put thin plastic sheet between the back of the board and the cover, plus I'll put a longer screw in one position that seems to function as a spacer. More to follow.

Any suggestions?

[maxnix]

Maintenance history? Filter change intervals? BG44K?

[GerryO]

One-owner dealer car (me), since 1993 with all new belts, front seals, water pump, etc, a few thousand miles ago (parked just as soon as I noticed the small water pump leak) the engine (172K) has never been over-heated or otherwise abused. About 20 mpg based on our last two fill-ups.

Which filters? Oil and air filters are new.

It started fine again this morning, after I first checked it for stored codes.

11 - probably because I attempted to start it with the Camshaft/Crankshaft sensor cable disconnected

51 - an EGR valve issue?

My question is now, why wasn't I able to check/display codes before and could 51 codes/issues be caused by a flakey ECM?

[maxnix]

Fuel fiter? Ncie to be new, but what are the cahnge intervals?

No mention of intake path nor fuel system maintnenance beyond air filter change.

[GerryO]

All was OK on the way to work this morning (about 7 miles of city streets).

This evening about a mile from home the Check Engine light came ON and the car ran rough and was under-powered.

Parked it in the driveway and disconnected a few injector connections one at a time, noticing that disconnecting one didn't make much difference in the way the engine started and ran. Disconnected and reconnected all six of 'em, including a number of other under the hood connectors, using dielectric grease too.

Re-connected them all, started the engine and the it ran normally again and the Check Engine light was OFF. Took a four or five mile test drive, stopping at two different stores, dumped in a bottle of fuel system cleaner, drove home and called it a night.

Tomorrow we'll see what sort of Groundhog Day deal I've got going, and will be changing the fuel filter.

[maxnix]

Fuel system cleaner? BG44K , we hope. Techron is OK, but won't do much. All else probably ineffective or worse.

[GerryO]

To and from work today, and all was normal - no Check Engine light and no rough idle.

It was Techron and after a bit of reading today, I hope it does no harm.

Bring on tomorrow.

Thanks!

[maxnix]

Techron is Vitamin C, BG44K is steroids.

Also consider a bottle or two of ISO-Heet (not HEET) in case you have some condensation or bad gas.

Keep us informed, please.

[GerryO]

A bad run all the way, to and from work today.

With the engine idling roughly and the Check Engine light ON, I disconnected and re-connected the wires to each coil pack this evening, one at a time, detecting NO change in idle speed at the cylinder #5 location.

I swapped cylinder #3 and #5 coil packs and the problem stayed with the #5 cylinder.

Measured the cylinder #1, #3 and #5 injector coil resistances at about 11.5, 11.8 and infinite, respectively.

Since I replaced all of the belts, water pump, etc a few thousand miles ago, I'm considering replacing all six injectors, the PCV valves and the EGR valve?

Is there anything else that I should do at the same time and which is the best new injector to go with?

Could a short have taken out the injector coil?
Modified by GerryO at 4:27 PM 3/20/2008

[maxnix]

No, but ethanol is a killer on the single pintel injectrs used on early VH45DE in particular.

Get a new injector

http://www.infinitipartsusa.com

Ther is no such thing as a refurbished injector. The coil windings are never replaced.

Try the BG44K first, a couple of times.

http://www.bgfindashop.com

[GerryO]

Agreed, the replacement will be a new one. They have the ethanol thing figured out now?

BG44K can repair an open/discontinuous coil winding?

I suspect that the others may fail as suddenly and completely as this one did, and considering how much work it is to replace just one the correct way, I suppose I should just do 'em all at the same time. Ouch. Other suggestions?

More to follow.

Thanks, Gerry