88 GM Box Upgrades. Heads, Cam, Exaust

[turbo2256b]

Did you mean 19# injectors or 17s. The injectors have to be the ones the ECM was programed for. Injectors have different spec's. The only way to swap in different sizes is to program the computer differently. Mass air setups the MAF can be ofset to inable the use of injectors to make them compatable but dosent realy work right so dont go that route.
nOT FOR SURE EXACTLY WHAT PARTS YOU HAVE USED but a 75mm TB is realy too big. Engine mods that would realy work best with a 75mm TB the fuel lines would have to be changed from the tank and fuel rails upgraded. A 75mm TB wont match up with a 75mm MAF.

If the cam you used is that .525 lift mentioned it will wack out your injector firing timing. Takes a lot of calculations and programing of the computers in your ECM its related to intake valve closing, some are figured based on intake opening

[gadget73]

There are actually specific baro sensors. Its a MAP without a tit for a vacuum hose. Or you do it cheap and just leave the hose off. I'm rocking an original 1986 MAP as a BARO on my car.

[sly]

correct. Use as a barometer sensor instead of MAP (same part, same wiring).

[andrew_mccaffrey]

The MAP sensor vacuum hose just needs to be removed right? not plugged...?

[sly]

+1 bad maf or wiring backwards.

[andrew_mccaffrey]

So everything is back together and it started up first try, but it wanted to idle at (im guessing) 3500 rpms!

i know the pic shows the MAF and ECU not wired up. It is now.

It smelled pretty strong of gas and it would only start at wide open throttle. So I thought maybe it was running to rich from the 24# injectors so I put in the 17#'s and I am able to start it with out using the throttle and adjust the idle to a decently low level, but it will only start with the MAF unplugged. When I plugged in the MAF it revs up and down (maybe trying to learn and adjust) then it usually dies, a few times it was able to idle for an extended period of time, but when i shut it off and tried to restart it, it wont idle. I tried to take it for a test drive down the block with the MAF unplugged (since thats the only way it will idle), it still seems like its running super rich and it completely lacks power. like full throttle goes 0-35 in 60 seconds slow.
When i check the timing, without the jumper I sit around 12 deg. When I plug the jumper back in, which in my understanding allows the computer to adjust the timing, it tries to advance it crazy amounts. its inconsistent but generally past the last measured markings over the "BTC" engravings on the balancer.
Also, I deleted the EGR which I know will cause it to run more richly, but I wouldnt think it could cause this much trouble.

My thoughts on this and the order I plan on checking things, let me know if im on the right track or not.
-because of the obvious smell of fuel and the fact the computer is trying to advance the timing so much. its running extremely rich
-I will start with MAF checking voltages and cleaning the MAF as it was a junkyard pick and could be bad. plus its the only thing that seems to create change plugged in or not.
-then I will make an EGR jumper to show as closed to the computer. found a diagram online on how to make one with a few resistors.
-then check all other sensors for voltage output and resistance (I read about a guy with an F-150 who had a fouled temp sensor and he said the signal it was returning to the ECU was telling it that it was -40 degrees outside and it was dumping fuel (this seems highly unlikely)
-I think that the complete gutlessness of the car is being cause by compounding factors. One, its running soo rich its getting crappy combustion; and two, the computer is F-ing with the timing so much because of the rich condition that its completely screwing up any chance of power.
-I have already checked for vacuum leaks and made sure to plug all of the no longer needed hoses, but if I can get it to idle reliably for a good period of time I will check the vacuum with a gauge.
-Multiple times already I have checked and double checked that I have the New HO firing order wired up, I will inevitably recheck through out this process.
-I have ordered a code reader, should arrive monday. then i will check for codes.

Thanks for the help! this stuff is fun, but confusing.

[Mr.Blue]

Looking good!

[andrew_mccaffrey]

Thanks for the info! good to know about the tuning. we'll see how mine turns out.

First step is complete! Took everything apart this afternoon with the help of a friend. I will start clean up and reconstruction tomorrow morning. Here is a time lapse of everything coming off. https://www.youtube.com/watch?v=ckn1...ature=youtu.be

[merc91]

That cam being 112/108 is not going to have vac issues to mess up speed density but I would go a9 "L" or "P" with the mass air.

A really good cam is comps xe258, way better than an ho cam and 1.7's never mind the explorer cams. High lift, low duration, low overlap is where low end power is made on a street driver especially with oem heads that peak flow in the 3000-4000rpm range.

19lb injectors can handle any stock ford head/intake combo NA ofcourse. Mine started to lean out past 6000rpm after an all out porting, port aligning, reconstructing of the heads/lower/upper/75mm tb/ tapered 4"-3-1/4" cold air pipe with a turning vane and more tricks. 19lb injecters can do quite a bit.

Good work with the exhaust choices.

For heads, a 160-165cc aluminum head is best for daily driver power, next in line is gt40P, gt40, and HO noticibly furter back. You can never have to much flow, however the larger the port cc, the higher the powerband will be. Porting heads isn't worth it unless you really know what you're doing... only 1 way to get exerience is try. Both for power and for strength of the port walls. But Port aligning is never mentioned, it can be easilydone and nets some good gains. Loose bolt down your heads than do the same with the lower intake, it can slide about 1/8 back and forth for closest alignment but a look down the runners will show ledges to dremel down so the head ports are flush or a hair set in from the lower's port edges. I mark the head/intake/and gasket best alightment on the motor than take it apart, lightly superglue the gasket to the head or intake, and port match the intake 1/32 smaller, and the head 1/32 larger than the gasket port.

I would definetly recomend explorer upper and lower intakes, I will post within the next few days with pics of the in's and outs to porting them, there is much to be gained from already good pieces that a 1st timer can usually manage quite well.

You can't go to big on filter/intake pipe/tb/egr. Sizing starts it's role at the mouth of the intake runners.
I went with a performance products cheep 75mm tb and the lever flips right over perfect to work on our drivers side setup, smoothed out the tunnel and thinned the blade post/screws, and adjusted the full throttle position the have the blade EXACTLY straight... Air speeds can hit 200mph, stick your hand out the window at that speed and tilt it 1/2* to see just how much energy air uses on you hand lol. We start with 14.7psi atmospheric pressure, than every little bend/friction/bump and turn takes a little bite out of that on the way to the cylinder.
I got a fire really cooking out back and melted some aluminum down, poured it in the voids in the egr spacer than milled it flat afterwards to essentially make a solid egr spacer. You can also just go buy a solid stang spacer. I bored it to 76mm. Than I just drilled and tapped the firewall side to mount the throttle bracket to. It's easy enough.

The a9p computer with a ho or explorer setup works perfect, even with the higher LIFT aftermarket cams, you don't need to get it tuned. I went through with the half day $600 dyno tune stuff expecting my missmatch of parts to need it, gained 1hp. A/F ratios, spark, and all the drivebility aspects, mileage were perfect to start with. This was with a 75mm cobra maf sensor.

[andrew_mccaffrey]

No real progress yet.

The heads with rockers. 75mm Intake and throttle body, A9P, 75mm mass air sensor, cam, 24# navigator injectors And 2.5" headers with dual exhaust are all purchased and waiting in the garage. The mustang tuning guys I spoke with quoted me about $500 for the chip and a tune, depending on hours. Right now the plan is to get started on this project the weekend after Thanksgiving.

[Mr.Blue]

Any progress on this mess? Lol............its kind of hard for the "been there done that" guys to give advice without knowing what you really want to "do" with the car so things kind of wander around in the opinion area.........

[pantera77]

Honestly I'd just stab a HO or Cobra cam in it, throw in a HO SD Mark VII comp. and not worry about it.

[turbo2256b]

GT 40s ported or E7s with the lunati cam mentioned would still be best ported. Intake a eDDELbrock #7125 with no more than a 65mm TB, first year cobra ECU with 25# injectors. Wire up stand alone speed control. Cobra ECU might even have speed control but never used it if it did when I HAD THE COBRA ecu IN cREAMY .

[pantera77]

Almost all aftermarket heads flow too much for a 302 unless going all out drags. Best is ported gt40s or dooe heads. If I KNEW ALUMINUM HEADS WERE BETTER FOR A 302 they would already be on my engine. Becides that there are no stock port location intakes that flow better than about 180 190 cfm. I have ported all of them and dont come much closer to 220 that E7s can flow.

Never said he had to go aftermarket, gt40's or p's would be a solid upgrade ever 37's though

[turbo2256b]

Mark VII's were all SD IIRC. Don't spend money on porting e7's, have at it yourself, there's a few DIY guides on them out there. Otherwise leave them stock and save up for some heads that actually flow half decent. 19#'s should be enough, the heads will be the choke point.

Explorers use a completely different ECU, not compatible at all.

You'll still need a mass air computer for a tune anyways.

Almost all aftermarket heads flow too much for a 302 unless going all out drags. Best is ported gt40s or dooe heads. If I KNEW ALUMINUM HEADS WERE BETTER FOR A 302 they would already be on my engine. Becides that there are no stock port location intakes that flow better than about 180 190 cfm. I have ported all of them and dont come much closer to 220 that E7s can flow.