RCWD21 Posted August 8, 2023 Share Posted August 8, 2023 Just recently did a mpfi swap on my 87 and everything has been fine until I swapped to some different injectors. After that amd at random (2 or 3 times so far) when I turn my key on the battery light will flash and the small 3 pin main relay under the hood on the passenger fender will click in unison with it. I can start the engine normally and everything works still its just the relay clicking and battery light flashing that worry me. Sent from my SM-G998U using Tapatalk Link to comment Share on other sites More sharing options...
adamzan Posted August 10, 2023 Share Posted August 10, 2023 I'd check the wiring circuit for the light. It goes go through several junctions IIRC and there could be a wiring fault or a bad relay. Also is it the same alternator the 87 had? Link to comment Share on other sites More sharing options...
RCWD21 Posted August 11, 2023 Author Share Posted August 11, 2023 (edited) Wiring checks good and no its got a 125 amp alternator from a quest installed since I run a winch and lights, etc. I do suspect that it may be a flaky relay on the inner passenger side fender (that tiny 3 pin one) the mpfi donor had 310k on it so there was definitely lots of use on everything. I've unfortunately had to sideline this issue as I'm chasing my tail trying to resolve a misfire that comes and goes below 3500rpm. I've swapped everything except the ECU, TPS, O2 sensor, and Igniter chip. It also dropped to 5 cylinders on me on my way to our shop today so I need to make sure an injector hasn't quit on me. I got some oem used ones from a vg33 so I could have the newer connector after fighting with cheap ebay ones that were just way too big on fuel delivery. Edited August 11, 2023 by RCWD21 Link to comment Share on other sites More sharing options...
Slartibartfast Posted August 11, 2023 Share Posted August 11, 2023 Might be the relay, though I can't say I've heard of one flashing like that. Easy enough to swap and see if that clears it up. Is it flashing slow, fast, irregularly? What year was the harness donor? I'll look at the diagram and see if something jumps out at me as a possible cause. Does sound like you've lost an injector. I have not heard much good about the eBay ones. I can't think of a way they'd mess with the battery light, though. Link to comment Share on other sites More sharing options...
RCWD21 Posted August 12, 2023 Author Share Posted August 12, 2023 The light flashes about the same speed as the turn signals do maybe a touch slower. I have a video of it but obviously can't post it on here. The donor vehicle was a 91 and I've been through the entire harness adding in intermittent wipers and cruise control and removing ABS and the rear door wiring. I never modified the engine side of the harness except for the vg33 injector connectors. I did post the vid in the NPORA group on fb though. As for the injectors I replaced one with another seemingly new injector I had found in a u pull it yard. It appears to be OEM as well luckily and it runs a bit better and I can even reach the rev limiter for the first time since I bought the rig back in 2015. Link to comment Share on other sites More sharing options...
adamzan Posted August 14, 2023 Share Posted August 14, 2023 The aftermarket injectors are hit or miss. I try to find good used OEM or pony up for Bosch or Hitachi parts. Can you post a link to the video here? I was the admin for the FB group but have since left that toxic platform lol. Link to comment Share on other sites More sharing options...
RCWD21 Posted August 14, 2023 Author Share Posted August 14, 2023 Its gotten so bad on there. And I'll try a link to my post and I have another video I took this morning of how the vg33 injectors are doing. Fb link: https://m.facebook.com/groups/NPORA/permalink/10160270193930129/?mibextid=Nif5oz Here's a link to the vid from this morning. To add to things, there's no dark smoke or smell of flooding with fuel. Just a touch rich from the engine being cold still. https://www.dropbox.com/scl/fi/fwsawa9etzw9zcgdddj2y/20230814_091321.mp4?rlkey=pwg3zgcgyribpy2b17wf9bwry&dl=0 Link to comment Share on other sites More sharing options...
adamzan Posted August 19, 2023 Share Posted August 19, 2023 sounds exactly like mine did when it dropped an injector I would check them with a multimeter hot and cold. They should be around 14 ohms Link to comment Share on other sites More sharing options...
RCWD21 Posted August 19, 2023 Author Share Posted August 19, 2023 I have 6 remaned injectors coming in from rockauto hopefully Monday that I'm going to install and hopefully it'll solve all of my issues. At this point everything but the TPS and ECU will have been swapped. My crappy Chinese injectors were too rich, these used oem ones seem to be lean, and hopefully the rockauto ones will be right on the money lol Link to comment Share on other sites More sharing options...
adamzan Posted August 21, 2023 Share Posted August 21, 2023 Fingers crossed! Last time I had to replace one the local parts house special ordered me a Bosch or hitachi one, can’t remember. The guy at the counter refused to sell me the normal brand they carried, didn’t want me coming back because “they’re hot garbage”.Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
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