Vb sle injected 5ltr 5spd electrical problem?

[Bigjase78]

Hi I'm hoping someone can point me in the right direction with this electrical issue I'm having with my vb sle. About 7yrs ago I done the injected 5ltr 5spd conversion myself accept for the wiring.I have always keept it well maintained I give it regular services oil plugs leads filters dizzy cap rotor button and its never missed a beat couldn't be happier with the old girl that was until a couple of weeks ago, It would backfire throu throttle body n splutter then take off then started running ruff when cruising round town usually between 60 & 80ks didn't have its usual nice quick smooth pick up but if I dropped it back to second & booted it away she goes no problem clean crisp like there was nothing wrong. Slowly it got worse but why? What could be causing this? I checked plugs leads dizzy cap rotor button coil swapped ignition modules stil same problem? Then just as got home left it running while opened gate & shed jumped back in to put it in shed & cough splutter pop bang throu throttle body chugg chugg roar back to life pull up in shed & it died.... Fuel pump starts throwing tantrum cutting on and off thermo fan starts doing the same I turn ignition off & wtf thermo fan clicks on & off the light in elec aerial switch comes on with thermo goes off with thermo??? Hmmm ok try start it again turn ignition on fuel pump splutters on & off cranks ova starts for 1second and stalls? Turn off ignition thermo turns on & off light in elec aerial goes on & off with thermo. Try again this time no fuel pump at all replaced relay still no fuel pump? Checked oil pressure switch all good ok removed fuel pump relay connected external power supply to fuel pump & works perfect crank it over same thing starts for 1sec & stalls? Try again but held key in crank position just backed off key till starter disengages & engine keeps running bit erratically idoling up & down let key go & it stalls? Also if I leave efi & fuel pump relays in they get hot even when ignition is off. I checked all earths, alt connections fuses and all were ok. Please can someone make sence of this & point me in the rite direction! Any help will be much appreciated.

 

[Nut Kracker]

Hmmmm. Might sound a bit strange, but check the ignition switch.

 

[Bigjase78]

Ok thanks I will give it a shot also if I leave the efi & fuel relays in they get hot even with ignition off would the ignition switch cause that aswell?

 

[Bigjase78]

Ok sorry been bit slack lately but I have replaced the ignition switch and still got same problem? Any other ideas?

 

[Cheap6]

No, the relays shouldn't get hot with the ignition off. That would indicate to me that there is a short somewhere. The most obvious place to look now is to go over the wiring that you did as part of the swap. Bad earth connection? Undersized wire(s)? When installing extra electrical components it's easy to overload a circuit. Are there any wires on which the insulation has hardened.

Old wiring often corrodes too. Anything that has wires with a green oxide coating or a crunchy feel when you move them?

I would have said ignition switch too. Is the replacement known to be good?

One thing re. the ignition switch is, where the car was previously running a carburettor, the ignition switch will not always (by design) have the "ignition on" terminal connected to Voltage while cranking. The result is the engine fires while cranking and a stumble or stall as the switch is released back to the run position. If the engine has enough inertia and the switch releases quickly the car will not stall so you might not have picked it up. That won't be part of your current problem but may be something to check later; that the new relays that are powered with the ignition also have power while cranking.

 

[Bigjase78]

Thanks cheap 6 iv been throu all the wiring and replaced and soldered majority of connectors and soldered any other wiring I came across that I thought should be soldered that weren't. I also found that even with the computer unplugged the relays still get hot! I kno there must b something small that I'm over looking so iv got a mate whos an auto elec coming on Monday nite to have a look. Il let uz kno how we go. Thanks for tryin to help solve this mystery I appreciate it allot! Ill keep uz posted.

 

[Bigjase78]

Finally gave in and got SaBBy from Sebs installations to have a look at the sle for me and suss out wat the problem is. Well the original auto elec that I got to wire up the sle injected conversion and external fuel pump for me wired the relays for the fuel pump and ecu incorrectly causing them to draw against eachother creating all these problems to occur. I don't know how this could have happen after 7yrs of electrical trouble free cruising. But we swapped the original Bosch relays for some narva relays and winner winner chicken dinner everything bursts back to life just the way it should. Iv got no idea why after 7 yrs this has suddenly happen when nothing had been altered or changed. Another big thank you to SaBBy from Sebs installations Geelong for finding the cause of the problem and sorting it out for me... Can't thank you enough SaBBy! If anyone wants a custom sterio, alarm or any other auto elec work done in geelong area check SaBBy out on Facebook at Sebs installations an drop him a line I'm sure you won't be dissapointed!

 

[Nut Kracker]

Good to hear you got it sorted and that you found a decent auto elec.

 

[Tasmaniak]

Pardon my ignorance but if all he did was replace relays that he says are wired incorrectly... Then is not fair to assume that this issue would reoccur?

I as an auto elec would say straightaway the relays sound a bit iffy. If they were wired incorrectly then you would have issues from the get go. Not seven years down the track. The relays were getting hot when off was because they weren't letting go, hence why you were getting some things trying to switch back on. So either he has replaced the faulty relays that have simply worn out and the issue is resolved permanently and your previous auto elec did NOTHING wrong. Or, he did something wrong causing the eventual failure of the relay but your new auto elec has hasn't fixed it properly and the issue will reoccur.