dirtyrobinson

I have been searching the forums for a couple hours now reading up on injectors and I could not find the answer to one of my questions. How do you tell what size (pound) injectors I have/need? I have an 85 but in 2002, the previous owner had redone the engine/transmission and the receipts aren't very clear if it was a rebuild or the whole engine was replaced. The injectors are yellow, if it helps.

I'm still trying to find the cause to my starting problem, I just can't for the life of me figure out why my car struggles to start when its hot. I know that opening the throttle body to let fumes escape helps it start but it still fires up very rich. I'm leaning towards the injectors.

Also, I was reading up on how to test the injectors. I am only able to test them on an ohmmeter at this time and the results currently are quite interesting. First I would like to ask, for clarification, is it best to test the ohms on injectors when the engine is hot/cold/whenever? I tested them while it was hot and my results are a little surprising, it has me confused.

Since I'm not 100% sure on the cylinder numbering, if someone has a chart that'd be a great reference, but starting with the drivers side/front cylinder I get 16ohm. Next one is 5ohm, 5ohm, the back cylinder on the drivers side is also 5 ohm. The passenger side/front cylinder is also 16ohm, and the other 3 are at 5 as well. I'm hoping the results are wrong if the car is warm

Since 90% of the fuel injector posts start with "call John at FIC", I may end up calling him to pick up some new injectors.

Cliff Harris

On the injector resistance: anything NOT near 16 ohms is BAD.

The cylinders are numbered 1 - 3 - 5 - 7 (front to back) on the driver's side and 2 - 4 - 6 - 8 (front to back) on the passenger side.

The yellow injectors are probably Accel (relabeled injectors from Ford Motorsports). They are usually 24 lbs/hr. I don't know what the stock flow rate is for '85. My '86 is 22 lbs/hr, but I think the '85s were different. One other detail is that the flow rate is related to fuel pressure and the Ford injector flow rate is measured at a different fuel pressure than the GM injectors, so the numbers aren't a direct comparison.

Jon is a very knowledgeable guy and he'll steer you right and treat you right.

joe paco

Cliff Harris is correct: anything less than10 ohms is considered a defective inj. warm temp won't bring these into the 16 ohm norm.

I think it's more than curious that so many were at the same resistance, rather than more random. have never heard that before, for the Rochesters or the Bosch, anyway. sounds like two different populations.

Jon can tell you for sure.

TorchRedlt4man

Have you spoken to Jon, yet?

dirtyrobinson

I unfortunately had way too much going on this afternoon that I forgot to give him a call. It will have to wait until Thursday with the 4th being tomorrow. I'm also trying to avoid working outside :-P, it is ridiculously hot outside (about 100-110 with the heat index).

As Joe said, I was also very surprised to see 6/8 at 5 ohms.

Since I'm not 100% sure if the engine in the car is from an 85 or not, I'm trying to figure out how to identify the engine. I'm sure Jon would like to know that too before I call him so we can figure out just what I need.

And, thank you Cliff! I don't know why but my choices of "words" in searches on the forum and online didn't really yield me any results with cylinder numbering.

Cliff Harris

I don't know a really obvious way to determine the year of the engine, except that late '86 and newer have aluminum heads.

dirtyrobinson

Update:

For whatever reason, I checked the ohms on the injectors today and they were all at 15.0-15.2. The car has been sitting for a couple days so this is a "cold" reading.

And I'm still trying to figure out if the factory engine is in the car or not. I'm not finding any badge or casting numbers on the block

dirtyrobinson

Update #2:

With a clear tube hooked up to the FPR, there isn't any sign of gas in the tube but it smells like gas. There is also a definite sign of fuel in the intake. If the diaphragm was bad wouldn't there be gas in both the tube and the intake? And if gas is only present in one of those locations, does that mean it's not a problem with the FPR?

AGENT 86

Your hot injector readings and hard hot starts, points to those injectors.
They could be Accel injectors, which have had some bad history.
Try your hot readings again, to be sure.
85 used 24# injectors.