I’m trying to resurrect a KR Corrado, so CE2 fusebox. I’ve replaced 2 main fuel pumps with new ones. Both have mysteriously died electrically. I suspect the lifter pump has also died, but haven’t removed it to check. There is battery voltage at both the fuel pump connectors. I have tried testing the latest one directly to a battery and it is a doorstop (although on reflection I didn’t take note of polarity at the time). The fusebox wiring looks ok, however my old stereo amp spontaneously combusted recently as well. The amp has it’s own 12v circuit and fuse so it should have been independent. the car has been on charge and I’ve only cranked it once. All I can think of is overvoltage. Has anyone any ideas what might be killing fuel pumps?
if the lifter pump is dead this puts strain on the main pump as they dont like having to suck fuel up out of the tank. that plus a constant supply of fuel is needed to lubricate the internals could explain why you keep loosing pumps. that being said if they have only been run for a short time I wouldn't expect a meltdown so quickly... have you tried wiring the main pump backwards some have found when they did that some piece of debris was spat out and normal service resumed. are the pumps genuine bosch items or no-name brand? over-voltage is easy to confirm with a multimeter, but to test the alternator the car actually has to be running thats the thing here first thing I'd do is remove the voltage regulator for a visual inspection, and clean up all the electrical contact points on it. theres one around one of the fitting screws and another on the inside which contacts a metal prong. That and inspect the brushes on it obviously
I have had this very problem with the "Wolf R", which is has been off the road for a while. Obviously the Wolf R is a MK2 and I did not want to replace the gas tank with a MK3 item as I had no leaks on the underfloor pump housing. The line internal to the lift pump had become rotten, so I also swapped that pump that for another working unit I had in my stash. I bought a brand new main pump from GSF, with the Bosch writing etc and fitted to the car. Great, car ran. Came back in a month to move the car and it would not start. I do not mess around making my self and arse with wiring. that is usually pretty durable unless other folks messed with it. That is not the case with my car. I learned usually it is the last new thing you did which is the root of the error state. So I whipped out the F/P relay for a relay 18 and there was no sound from the pump. Jacked the car up and got direct battery volts to it and it was solid. But the pump was new! A bit pissed at having to buy another pump, I took the pump apart and unseized it. Reassmebed after a test run and all good. Came back in two days and it was seized again. At that point I had enough, bought a MK3 VR6 12v gastank with all the lines etc and that was the end of it. Was not 100% for the fittment of the MK3 tank to the fuel flap area but after a bit of jiggling around it was acceptable with all the fitting added. Meanwhile the original main pumps in my G plater 16v (with a V6 24v), J plater 8v ( with a modified ABF engine) and a Cabrio 1.8 GTI ( with a 20vT) are fine. But I have had not luck with aftermarket replacements when I last tried.
The Bosch 60mm 191906091H Corrado pump is NLA as far as I can tell. Both of these pumps were Magnetti Marelli. I'll check the Voltage regulator but as you say, it is difficult to check alternator output without the car running... Toyotec, I'm not entirely sure what you are suggesting - clean out the fuel tank or replace the pump with a ? The Corrado at least shares a tank with the G60 and VR6 versions so in theory an in tank pump from one of those would work as a lifter pump. As far as I can tell the K-jet lifter pump is rated at 3.something bar which is more or less the same as system pressure for Motronic or presumably Digifant etc so presumably that would work. I'm just not sure how that will stop me burning out main pumps. Still, cleaning the fuel tank won't hurt I guess.
Your pump is seized not burnt out. Over voltage etc is not how these cars work generally. I would not want to send you down a rabbit hole. Aftermarket Bosch branded CIS pumps seem to seize shortly after replacement is my experience. The car I spoke about is no longer Kjet but a 16vT with aftermarket EFI type injection. I retained the Kjet main pump as it had the flow capacity for the turbo engine, so it was natural to switch the gastank to a conventional system when I started to have issues, solving my problem. You cannot do that. Other cars I have with the orignal Kjet pump are fine, including one with a 24v enngine. Admittly those vehicles are in constant use. In hindsight, it is possible your gastank needs cleaning which is why you are seizing replacement pumps. Hope that helps.
