This issue has been plaguing us since we got the car last year. Car was/is dead stock '89 L98, takes forever to start when cold and smell like raw gas. Hot starts, maybe two revolutions no problem. Once it catches it settles into a nice smooth high idle and kicks down after about 30s like it should. Tip in hesitation is really bad but revs freely once its past it, drivability is ok once warm. We removed the A.I.R. injection system and factory exhaust and replaced with Dougs headers, y pipe and a magnaflow cat back. Brand new Bosch spark plugs and O2 sensor from autozone. Accell extreme 9000 ceramic boot plug wires. New cap, rotor and coil. None of this made a bit of difference.

I know someone is gonna ask, and yes, I do still have the original two tone Multec injectors in there and we are planning on replacing them along with the FPR with some 24lb D3 from southbay. We also have a NOS distributor to drop in when we do the injectors. Is there anything else I could be missing? I can't imagine there is anything else but every thread here seems to be about hot start issues or cold start injector. I do have a motes prom adaptor in the ecm so it's no big deal if there are changes i can do to the prom to help as well.

 

Any fuel in fpr vacuum line ? Fuel pressure drops after prime ?

 

These are things that have been on the list to check but have not been done because we've been focusing on replacing wear items and getting it up to date.

 

guess I’m not following the point of the post

 

I'm 90% sure at this point it's either the injectors or fpr, but want to make sure there's not something else that I should be replacing while I have it all apart.

 

Don't put 24 lb iniectors in there unless you plan to retune.

Is this a 305 or 350?

 

Might do the rail o-rings , standard motors sk24

 

looks like a 350, he said he can tune so 🤷‍♂️
unless your doing a cam swap or heads I’d probably stick with the d3 22#hr

 

I have a set of world sportsman ii heads already, so a full .030 over refresh with cam and stuff are in the cards in the next few years. I'd like to avoid buying injectors twice.

 

Right so this is helpful because I wouldn't have thought of this.

 

https://www.thirdgen.org/forums/tech...gh-idling.html

the sk24 will have 3 unused o-rings for 89 up tpi

 

Replaced the injectors with 22lb D3 from southbay, the fuel pressure regulator diaphragm even though it looked like it was new, o-rings on the fuel rails, and the distributor. Fired right up. The real test will be next weekend, a cold start after sitting for days. Now on to the next problem.

 

Just curious can you monitor fuel trims ? I’m wondering if the D3 are lean in closed loop. Some people have issues while others seem to be okay.

 

I do have a cable and laptop, I did a little testing last year but all the drivability issues put a damper on really messing with it. I do plan on a deeper dive to see how it's performing. I know I can get live values out of it but not exactly sure how to log, shouldn't be too tough to figure out though. I do know I need to edit the bin to account for the air injection being removed so that's something else to add to the pile.

 

It would be cool to compare before and after voltage offsets. $6E isn’t to difficult to connect to the 165 ecm and use tuner pro rt.

https://www.thirdgen.org/forums/diy-...0-voltage.html

 

Ok, so I changed the Injectors, FPR diaphragm, o-rings all of it. Still had a hard time starting and would bog real bad on tip in, kinda drove okish once warm but not great. Changed the fuel filter today hoping that would do it, a ton of nasty stuff came out of it so hopes were high... Nope no change. Thankfully I got a new fuel pressure gauge kit that doesn't spray gas everywhere when you press the release button - about 25ish psi engine running and no change when taking the vacuum line off the fpr. ATP I can only think its a weak pump right? At least it works well enough to pump all the gas out of tank before I drop it.

 

Pinch the return line by the drivers side fender well to dead head the pump. Start the engine or prime see if pumps capable of producing more pressure.

 

Oh good! I feel better now, lol. I have always used that test method too, but always felt guilty about pinching the hose.

 

Hose clamping pliers, vice grips with a piece of wood to slightly protect the hose. But you can risk damaging an old hose. Just a way to diagnose.

 

So I don't know if or when I'm gonna have time to try this, but what would it tell if it can build pressure with a blocked return? Based on the amount of crap that came out of the filter I've pretty much resigned to pulling the axle and dropping the tank. If the pump is original it's got 112k on it and almost all of it was in Arizona, if not God only knows what kinda parts store crap got put in. So I'd rather do it now and be done with it. And if I remove the driveshaft I can get fresh u-joints pressed in and replace the torque arm bushing while it's all out, then the car is totally new underneath.

 

Pinching the return will see if the pumps capacity of producing more pressure. But if it’s old might as well clean the tank and replace. I’ve been able to drop the exhaust and the rear shocks and pan hard and get the tank out. No need to remove the lca trailing arms .