Car still stalls on startup if i dont give it gas, otherwise it runs pretty smoothly, I think its because I don't have the CSI hooked up, but since I am using 3.4 injectors on a 3.4 block that should not matter, I suspect its the way that the ECM is programmed to use injectors...its probably not setup for starting without a CSI in it regardless of whether or not the 6 injectors are big enough.

Otherwise its one of the sensors(I'm thinking tps or IAC), speaking of which theres some on the 3.4 that I am curious about, what is the one on pass side that interferes with exhaust manifold, what is the 2 prong block right above oil pan on same side, and what is the one on the driver side behind the oil filter if memory serves (it isn't the oil sensors).

 

How good is the MAF? Is it good? CSI doesn't matter much, as it just gives a small shot of extra gas until the engine reaches 100*F. Generally, my guess would be either a vacuum leak or the MAF is bad. Especially if you can keep the engine running until it warms up a bit with your foot and then everything is mostly fine and the engine runs by itself.

The 2 sensors on the pass side are the knock sensor (where the coolant plug was on your 2.8 block) and the 7x crank position sensor (down by the oil pan). You'll have to verify where the other one is.

 

Hmm, 2.8 deff doesn't use the crank one, pretty sure it doesn't use the knock one either,
would I need to use that 7x one to run DIS? Also I actually didn't have the MAF hooked up, was just a test fire, still have to do some finishing touches, before I run it for any length of time, vacuum system has the important stuff hooked up, pretty much identical situation to what I had with the 2.8, but I'll wait and see what happens with the MAF in, and I really have no idea if it's bad or not. But hell, I'm happy the thing actually fired with no drama, once I get the timing in it started right up, first engine not only built, but swapped by myself :P

 

Why do people do this?

They try to make something work with only part of what needs to be connected, and then go to a forum asking for help, and why thier gizmotron is not working right.

CONNECT EVERY POSSIBLE CONNECTION BEFORE ASSUMING THERE IS A LARGER PROBLEM

:facepalm:

Yes, the crank position sensor is used for DIS, disregard this.

You'll likely also want to swap to a later ECM, that doesn't used the CSI. Swapping to a 3.1 ECM would also change it from MAF to Speed Density.

 

its the csi the stock ecm will not add the needed fuel on cold startup to keep the engine running , the csi is actually not an injector but more like a controled fuel leak into the intake until the temp goes above the setpoint the injector just stays open .

heres a simple test pinch off the return line when the motor is cold and start the engine with it closed off chances are it will stay running since the injectors are now spraying the extra fuel since the fpr cant bleed off the fuel presure

going from stock to 3.4 injectors is only a small percentage in increased flow rate on cold startup the engine needs in the area of 20-30% more fuel to stay running

only the 3.1 ecm supplys this extra fuel during cold start unlike the 28 ecm which relys on the csi to do it

 

Chill the hell out buddy, was a test fire, nothing final, just trying to get answers to problems so I don't find myself in front of my car wondering wtf is wrong and then by the time i get answers im back home where i cant fix them. When I had the 2.8 in, I had this problem with everything hooked up so how bout you stop jumping to conclusions. I can't exactly get to my car easily atm either because its my only damn car and half an hour away at my mothers house atm.

 

Thanks dave, thats more or less what I figured. Any chance I could just turn it into a returnless fuel system, or run with the return line pinched? And if not, I don't suppose you have a 3.1 ECM lying around, also can't those ECMs run DIS as well? If so it would probably be worthwhile for me to snag one up till I get an MS setup.

 

the 3.1 ecm will run dis, as well as since your using 3.4 injectors the 3.1 ecm will also be a bit closer on the fuel delivery, pm sent i have a ecm and also a map for the conversion

 

Actually, if set up right with the right PROM program, the 2.8 ECM will also run DIS (same 4 wires). Yes, you can go just fine without the CSI, provided the injectors work (didn't use my CSI for a while and only had problems when I had a bad MAF). Also, about the only way to go returnless is to build a system to set the fuel pump to cycle (as in how the A/C works) or use PWM, as the newer fuel injectors do.

Oh, and the 3.1's 730 will require some serious rewiring (uses MAP, among other things, that the 2.8 harness doesn't have).

 

You need everything connected BEFORE you test fire, that way you can then be more sure that you truely do have a problem.

Leaving things disconnected, especially when you are unsure of thier function WILL cause you problems.

That is like trying to browse the internet without using a monitor. Yeah you could likely get around, but you're not seeing anything.

that's what your ECM was doing, guessing, based on pre-detrermined tables, running in Alpha-N mode, that is only meant to get you home or to the nearest repair facility.

Another analogy is "putting the cart before the horse".



It's not that bad actually, just repin a few wires, and either use the MAF wires for the MAP signal, or add a few wires to the harness, really it's not that bad to do.

I'm actually almost done making an adaptor harness to use a '7730 running code59 in place of the original '7148 in a friends Turbo Regal. I would have just re-pinned it, but it has 6 injector outputs on the harness and would rather leave them alone for the time being.

Going returnless fuel system would be difficult. The older OBD1 harware and software doesn't have provisions for it. I suppose if you were handy with doe you could use one of the non used PWM outputs on a '7730 to run a MOSFET based circuit to run a pump on a returnless system, but that seems like way more work than it's worth. Oh, you'd also have to right the code to use a fuel pressure snesor as well for the fuel rail pressure feedback. WOuld likely take up a fair amount of code space for something that a simple return fuel system has no problems with.

 

I know the function of everything on the engine, only things I was uncertain about is the sensors the 3.4 block has that my 2.8 doesn't, and even then, its not a matter of not knowing what they do, but which sensors were located where, as for the maf I left it off in case of a backfire or something crazy like flames out the throttle body, hence test fire..and ground fire...driver side header lit the grass up, scared the living **** out of me cause it was right underneath the engine and flared up pretty quick, i dove under the car and started flailing like all hell at it with my Haynes manual, most use I've ever got out of my haynes was putting out that fire

 

right now u are better off with the maf ecm considering head work and cam , i wouldnt suggest going speed density unless ur going to start tunning it right away out of the box the 2.8/maf ecm will run better with ur mods

 

I agree, before you start thinking there are problems, hook everything up the way (MAF, CSI, etc) it was before you did the engine swap. If there's a sensor for a 3.4 on the block, ignore it b/c it won't hook up to anything.

And it's a little late but you should always have a fire extinguisher nearby when starting up a motor like that- if not for your own safety, for that of the car- imagine if it melted to the ground after you did all that hard work! Otherwise, congrats on the swap...