TR surging

I have been driving this thing every chance I get. Yesterday i put in 1/2 bottle of Techron and filled it up with premium. Drove home no problems. Today I go out to run a few errands. 10 miles, 2 stops later during a static 40mph I feel a slight surging. I gun it and instead of the usual growl/acceleration, I get a lethargic increase in speed with spuratic jumps in normal performance. It is idling now at 800rpm while normal is 1100rpm. Slow revs. Engine temps are normal.

Im hesitant to point to the Techron as there are blips of normal performance. Im thinking a loose bad connection somewhere.

1990 US spec car.
Side note: The tach has been sticking/lagging since I get her. I dont know if its related but I thought I would throw that out.

Any usual suspects?

EDIT.....I swapped the Fuel Pump relays. Nothing. Im assuming the fuel pumps are the silver canisters behind the fuel filters? If so, the passenger side hums when the engine is running, the drivers side does not. thats why I checked the relays, fuses.

 

SON OF A B**CH.

Found it. The aft most, large cannon plug on the passenger side upper engine compartment (just above the VIN stamp on the frame) had come off. The 'The grooved tension ring' that you hand tighten the plug, is cracked thus not securing the cannon plug in place. I still cannot feel any vibration from the drivers side fuel pump.

Did a quick test drive......all good. Im sure Ferrari sells just the little ring....yea right!

 

Now that Im thinking about it......the things im referring to as fuel pumps cant be pumps as they have no wires connected to them. Correct?

Anyway, Im going to gently use a hose clamp to provide pressure on the cannon plug tension ring. Easy fix, secure and no billion dollar wiring loom bill.

Edit...Thanks Tim!! Is the extraction tool shaped like a metal straw that pushes back the prongs? IF so, thats a no-brainer! Thanks again, Ill order it ASAP.

 

Boy, that didnt take long for this thread to go south

 

All parts ordered from digikey...just under $30 plus shipping.

 

Got the parts from Digikey.com and started this little project.

Removed the 22 pin ECU connector and the 9 pin connector next to it. I also removed the 2 other rectangle ECU connectors so I wouldnt have to bend over for the next 3 hours. The 9 pin connector is behind the fender....but you get the idea. Now I could sit on a stool and save my back. I took my Dremel tool and used a small nylon brush attachment and CAREFULLY cleaned the male connectors on the car. There was some oxidation but a few seconds with the Dremel, shiny.



Next I took an Exacto knife and carefully cut the 3-4 inch heat shrink tubing allowing the wiring harness coupler to unscrew and slide down the harness. (see above pic)

I took a piece of paper and drew a wiring diagram showing where exactly where each pin goes. Then I decided not to chance it and removed one pin at a time then inserting it into the new connector. I started with pin 1, then 2 then 3 etc. This method insured that the wires would (A) be in the correct spot and (B) not be stretched / bunched up as my rewiring job would be different than it came from the factory. Using this method, the wires just seemed to 'want' to go into the new hole. You will hear/feel a click when the little prongs seat themselves.



Im glad I took Tims advice and ordered the 9 pin connector as well. Although it was connected, the teeth on the female finger screw portion were gone. Tension was the only thing holding it on. I suggest checking these folks. In the end, it was a 1 hour job and I took my time making sure everything went perfectly.

For the adventurous types, here is where all the wires go. Sorry for the hand made diagram....Im no SteveM


I had the ECU connector held together with a hose clamp and that worked as a temp fix.

Glad I spent the $30 and 1 hour of time to do it right.

 

Believe me, its on the list. I inspected the fusebox and there is zero evidence of overheating on the white connectors. Everything looks brand new. Makes me think that the PO spent the money and had things replaced. Ill continually inspect it every few weeks as part of my normal inspections. But it will be sent out to Mr Helms for an upgrade eventually.

I do have two mystery relays tucked next to the fuse panel. Don't know what they operate. Alarm perhaps or previous mechanic installed them in part of an overheating campaign. Im thinking they might be part of the alarm that kills the fuel pumps if triggered.

Anyway, the car fired right up and seems to run better than ever. The tachometer is working as advertised. (I did also clean the hell out of the RPM sensor while doing the above rewiring as it was filthy.) It was stuck on 1,000 RPM last night after the car got up to operating temp. Once cool, it was working. Took a nice 30 minute drive after repairs today in stop and go traffic and it still worked.

Short List: Replace passenger side window switch and redye the drivers seat bolster. Other than that, everything is functioning within normal parameters.