Originally Posted By: mechanicx
Originally Posted By: OVERK1LL
mechanicx: I was agreeing with you, that's why I said "I know where you are going with the lean thing and surging".
I will note that this is really only an issue with the SD EEC-IV; many of which were batch-fire.
The Mustang was SD only from 86 to 88, and was SEFI. 89-93 they were MAF, and arguably the best factory SEFI setup available. With a host of aftermarket support from a variety of companies, and being completely programmable via MOATS, TwEECer, SCT and the like. And VERY little in the way of emissions stuff to get in the way. It has been a popular choice for hotrodders of all makes to use on V8's and there are distributors to adapt TFI to both Mopar and GM engines because of this.
The SD version has its limitations however and the "tuning circle of surge" as I like to call it is one of them. There is always a culprit. But between the EEC telling you everything is in range (when it may actually not be.... We are dealing with 80's stuff here) and Ford's love for vacuum lines..... It can be a complete nightmare.
What's funny GM TPI on the Camaro while batchfire was MAF until 90 and then they switched to SD until I'm not sure '93 or maybe until OBDII. The Ford had SEFI I'll give them that, but GM never really had problems with batchfire combined with SD combined with a non-heated O2 sensor. Plus GM used plastic vaccum hoses that rarely leaked. Their TFI wasn't as good and reliable as the GM trigger and module, not to mention GM's crank sensor triggered DIS. Ford's probably are slighly more programmable/mod-able I'll give them that, but I totally agree their FI system was harder to work on. What with their telling you to use a breakout box, sometimes no check engine light, rubber vacuum hoses etc. I think Ford did a good job on their later Ignition systems and EEC V though.
PS: Demarpaint don't me to highjack your thread or take it on a tangent, but I think there's not much more that could be suggested for your surge at this point.
Ford had DIS later on in the 90's on the Windsor engines, most notably the 302 in the Explorer. And of course the Modular engines.
TFI was reliable if you kept it cool. Ford's big mistake was mounting the module to the distributor. This of course is why later EEC-IV vehicles had the module remotely mounted in a heatsink on the fender.... And go figure, didn't have the module failures like the distributor mounted ones did. TFI had much higher energy output than HEI, and could subsequently feed much higher output engines more reliably. With stock engines, this is neither here nor there though of course.
Ford's vacuum line stuff was just odd. Some of the trucks were a NIGHTMARE with the blend of rubber and plastic lines. I know my F-250 was. The Mustangs were not that bad, neither was my Townie. Decent mix of both. Though the plastic ones liked to break when they got old (and of course brittle).
The break-out box was only for early EEC-IV. And the ECM had the ABILITY to feed a CEL since 86. Many of the cars were simply not equipped with one however.
The system was designed in concert with Bosch and Intel, which is why many of the parts of EEC-IV say Bosch on them, and the ECM has Intel internals. It is a good system. And 89-93 is excellent. It has HUGE aftermarket support (primarily the A9x series of ECM's) because of how flexible and tunable it is.
I really have no experience with the GM stuff, but my understanding is that while excellent stock, it is no where near as moddable, at least not the stuff of this vintage.
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I agree with your point to Demarpaint. Unless somebody has an epiphany, it looks like pretty much every avenue has been explored.
