Fuel Injector Information
 

So if the Multec 1's are in 89 to 91's.... what were in 85 thru 88? Are they Lucas?

I OHM'd mine the other day in hot condition and they were all 17.7 to 17.9

Should I check them in a cold state? What should they read in comparison to when theyre hot?

Ive been considering changing injectors for a new set...

When engine is cold, (sits overnight)... it fires on the first touch of the key.
After its warmed up fully, if you try to start it up within a few minutes after shutting it down, it will fire right up. BUT, if you wait any extended period of time, it takes 2 sometimes 3 tries and more crank time than it should.

This had been going on since I bought the car and before and after all the full tune up, new fuel pump, filter and coolant temp sensor etc, etc. (The car runs much better than when I bought it for sure....) but the hard restart condition persists when hot after sitting.

So the only things left would be the FPR and injectors.... How do I verify?

My 86 has Lucas injectors. Don’t know if they are stock or have been replaced along the way.
Mine all OHM’d exactly what yours did 17.7-17.9
If mine has sat overnight it takes 2-3 revolutions to start but if the car if hot it is like a 1/4-1/2 of a crank. It lights up real fast.

I think 85-88 were Bosh 1.

Might check your cold start injector? Wonder if it's not firing under certain conditions?

Pretty much the opposite as mine....

Doesn't the cold start injector come into play when the engine is cold, and not hot? Sounds reasonable.... but I really am not sure.

I think you are right. I read the other reply and confused his issue with yours!

There is no such thing as Bosch1 or Bosch3 for that matter all the injector types are EV something EV1 EV6 there is no EV3

I would check for codes, fuel pressure, and timing. Scanner would be handy. You should be running regular not premium. If nothing showed I would try decarboning.

My 89 does exactly the same thing. I replaced injectors, FPR, even the ecu, but made no difference. I read an article somewhere that at least on the 89’s, it was a programming problem from the factory and a common one at that. It can be fixed by altering the program. I have changed some things in my ecu by using trunerpro rt and an ostrich, but I don’t know enough to work on that problem

:iagree: (sorta) -- pretty sure when folks refer to boschIII's, they are meaning the third design, which are indeed EV6 style injectors. pretty sure EV6 injectors went through several design revisions over the years. :rock:

I think timing could be an issue.... Today I hammered it a few times and could hear pre ignition/ detonation under heavy load. I actually use premium all the time....

For anything other than the most minor change it would get a new EV engineering series number.

Ok, so what injectors in my 86 L98???

You could read the part number off them. Being over 30 years old how much does it matter now as the odds of finding new ones is probably zero.

It doesnt matter... Im wondering if they are Lucas or Multecs... Im not trying to find the same ones.... Point is, I read that the troublesome ones were 89-91.... If I dont need to swap these, I wont. If I need to, then Ill get what I need as a replacement probably from FIC.

Post a picture of them

Heres one

It is pretty simple if it runs good do nothing if not determine why and fix whatever it is. Multecs are made by Rochester and historically have a smooth body with no reduced diameter section as shown in the pic. You should be able to take the connector off the injector furthest to the right in the pic and get a part number to google.

If you read my first post then you can see I have a start issue when hot after sitting for a while.... THATS why Im considering new injectors and after all the failures I see with guys and their Multecs, I thought Id check a few things out. Ill see if I can get that part number... thanks.:cheers:

FWIW, here's a pic of the GM multec vs EV6/3rd design injector (commonly known as boschIII).
https://www.thirdgen.org/forums/atta...difference.jpg

on the subject of boschIII's, here's a pic of the 3 current bosch designs --

https://cimg4.ibsrv.net/gimg/www.cor...52e3dd4c0f.jpg

EV1 or first gen bosch were used on early TPI cars. not sure when GM switched (backwards) to multecs. considering the technology at the time, original EV1 bosch injectors were, and still are a good design. I don't know who holds the design patent, but EV1 injectors are licensed and currently manufactured under various nameplates. not 100% positive, but i'm thinking there are 4 major EV6 designs. don't know the original EV6 applications, if any, but 2nd, 3rd, and 4th designs are commonly used. aside from size and design improvements, the major difference with the original bosch injectors are the number of fuel discharge ports - EV1 - single, EV6, 4-hole discharge port.

https://cimg9.ibsrv.net/gimg/www.cor...0fd2a81a13.jpg


:rock: