I've just had a stock 3.1 engine installed in my 86. The engine is rated at 140 HP, just like the Fiero 2.8. By all injector size calculators, it should be able to run on the Fiero injectors. I have had the injectors from my old 2.8 refurbished and had a failure on one of them upon startup. They were sent back with a couple of extras and they said they got 6 good ones. But the car is running horribly and I'm getting a Code 44, lean burn code.

Have any of you done a straight 3.1 swap and what stock GM injectors did you use? Is my problem simply that the lean burn is due to injectors not firing, or are they undersized from what was originally in the 3.1? I'm not interested in going to Accel injectors or installing an adjustable pressure regulator. I want the engine to be stock.

The 3.1 should be able to run on the 2.8 injectors, assuming they're in good condition. Just out of curiosity, have you checked the fuel pressure?

I haven't checked the pressure, but the rail and regulator is out of the old engine. So are the injectors, but I thought I'd have them refurbished before installing them. The old engine started with just a bump of the starter and idled at 1K without wavering. It ran perfectly until it decided to make milkshakes in the crankcase.

The 3.1 engine did run well on the 35 mile drive home from the shop and for a couple of days afterward. Then it started missing and the lean mix code set.

quote Originally posted by fierofool: I haven't checked the pressure, but the rail and regulator is out of the old engine. So are the injectors, but I thought I'd have them refurbished before installing them. The old engine started with just a bump of the starter and idled at 1K without wavering. It ran perfectly until it decided to make milkshakes in the crankcase. The 3.1 engine did run well on the 35 mile drive home from the shop and for a couple of days afterward. Then it started missing and the lean mix code set.

Charlie... I wonder if the tank got water - or even condensation - in it, while it was sitting.
I'm with Blacktree. I really think the engine should run fine on the stock injectors.

[This message has been edited by Raydar (edited 09-02-2020).]

When Scott and Mike installed the refurbs, it had a dead injector at first start. It was replaced and the car ran great other than idling a bit high. It had a fresh fuel filter on it, so I think it probably isn't sediment that's clogged an injector or two.

Sometimes it idles decently, then it will intermittently run horribly. Now it's just running horribly. It's possible there may be water in it. I'll see if I can't find some dry gas to burn the water away. Meantime, Zack is checking with Mark to see if he has a set of injectors.