Paulyy

Basically as the title says..

To run you though,

I had Speed & Reference sensor issues. So i replaced the sensors as per clarks garage, and a new LR S&R Harness.

Now i've installed it properly, I want to double check the sensor grounds on the DME though. (90% sure they're done right)

I have tach bounce, more the i did previously. it cranks, and it bounces but wont fire. I have spark, just no injectors. I do have fuel pressure

So yes, what causes the injectors not to fire?

I'm hoping i didn't damage a sensor. i did the 0.8mm gap with a washer glued to my old sensor.. I also had markings on the holder and bell housing from PO and when i put the motor back together i lined them up and it worked. When i did the gap to make sure, it's in the same spot.

TIA

Van

Fuel pump running? DME relay working (that powers the fuel pump, you know...)? DME OK? Wiring harness to injectors OK? Does it have fuel? (Don't laugh... a friend of mine recently had a no-start condition and it was because he ran out of gas.)

Paulyy

Got fuel, got pressure. no injector fire.

DME is ok. All thought i better check the chips.

Injector harness? not 100% sure.

DME relay.. good. I've got and tried a spare.

JFreeman

Have someone crank the car for you, while it is cranking grab the injector harness and wiggle it. I had this happen once, one bad wire caused all of the injectors to stop firing.

odb812

Have you checked that you're getting voltage to the connectors for the injectors? I'm guessing these injectors were in the car when it was running previously, right? I've heard that sometimes injectors need to be "woken up" but either way it would be good to know if the problem is the injectors or something upstream of them.

refresh951

Pauly - I think most likely you have an issue with the sensors. If the DME does not see proper speed and reference signals the DME will not fire. I would check the sensors with a digital multimeter set to ac voltage. Speed sensor should show around 2 volts and you should see a blip on the reference sensor when cranking.

Mayhem'sLV51

My guess is injector harness. I had to rebuild mine with pigtail connectors. Have you checked your injector conmectors with a multimeter? I'm afraid I may have a break further upstream, as the car stranded me and wouldn't start last week. Other than having spark, how did you verify your DME was in good order?

Mayhem'sLV51

Just curious, what was his fuel gauge showing? I showed 1/4 tank when I stalled and had a no-start. I have a ford that runs out of fuel at 1/4 because the pick up fell of in the tank.

Paulyy

I'll do that, thanks!

I'll try this too!

Because the DME was working previously before changing the sensors.
I'll check the harness

Van

It was a race car with a digital fuel gauge. It showed 3/4 tank, but was, in fact, bone dry.

Paulyy

I found my Volt meter, It's not bad.. Digital and can go duty cycles and other stuff.

I'll use clarks garage guide in making sure my sensors are okay Speed and Reference sensor guide.

Shawn, which pins am i checking for AC voltage?

Zeff

I think it is worth checking the DME for bad solder joints too. My car ran fine, almost a year on the Mtune then one day about a mile from the house it just shut off. I saw that I had tach bounce and remembered a thread where someone had to bang on the DME. I tried that and the car cranked immediately. I took the DME to a shop and they found 2 bad joints. They were the same joints that went bad in a thread I read on here that had pics. I haven't had any issues since.

Paulyy

I'll check that later. I'm more worried about the sensors then DME. I can fix the DME but not the sensors. I have had the chipboard fall out on me once. No clue how. but i'll be checking the DME too.

refresh951

Speed Sensor - Pin 27, Pin 8
Ref Sensor - Pin 25, Pin 26

Paulyy

i have resistance but no voltage