Z28 - Won't start Now
Discussion
Oh dear, I've been away for a couple of days so not been starting my car. Went to it today and it won't fire. I can smell petrol so I doubt if it's the fuel pump and the battery seems to be up. Any help Appreciated!!! The problem I had previously with it cutting out after about 4 miles had stopped with use.
Obvious question first... Is the 'check engine' light on?
The fuel pump on my '88 IROC quit and that was preceded by the motor cutting-out intermittently before it stopped altogether. Also might be worth checking power to fuel injectors - no pulse would indicate a bad module. Check the fuel filter too.
Finally, given the mileage (100k + according to your add posted elsewhere), check for an air leak in the throttle body (where the spindle passes through the aluminum casing on the linkage side). If it's drawing air into the plenum, the MAF sensor's signals to the computer will be all to b
ks (would give you an error code though).
The fuel pump on my '88 IROC quit and that was preceded by the motor cutting-out intermittently before it stopped altogether. Also might be worth checking power to fuel injectors - no pulse would indicate a bad module. Check the fuel filter too.
Finally, given the mileage (100k + according to your add posted elsewhere), check for an air leak in the throttle body (where the spindle passes through the aluminum casing on the linkage side). If it's drawing air into the plenum, the MAF sensor's signals to the computer will be all to b
ks (would give you an error code though). Try here
http://www.thirdgen.org/techboard/?s=e853b9aca75ed...
But check the fault codes.. always a good start.
My 2.8 V6 is playing up and overfueling so much it's gotten into the sump! Changed the Engine Temperature Sensor, seems they are prone to fault as is the plug at the other end, and am now getting a Mass Air Sensor from eBay in the US, $74 delivered! Hopefully that will do.
Good luck with yours
http://www.thirdgen.org/techboard/?s=e853b9aca75ed...
But check the fault codes.. always a good start.
My 2.8 V6 is playing up and overfueling so much it's gotten into the sump! Changed the Engine Temperature Sensor, seems they are prone to fault as is the plug at the other end, and am now getting a Mass Air Sensor from eBay in the US, $74 delivered! Hopefully that will do.
Good luck with yours
optispark = early 4th gen
They are notorious, especially on the 93 and 94 models, as I dont think they were vented. Later models had a vent to keep them dry inside.
If there is no spark then if its not your coil it could be the opti again.
Check the voltage going into the coil. I "might" have a spare stock coil, let me know if that is the case. Ill rummage around the shed
If its the opti, take a look at the aftermarket models, which are designed to address the stock shortcomings and consider a replacement with one of them instead of the oem next time.
Plus at that cost, Id do it myself!
They are notorious, especially on the 93 and 94 models, as I dont think they were vented. Later models had a vent to keep them dry inside.
If there is no spark then if its not your coil it could be the opti again.
Check the voltage going into the coil. I "might" have a spare stock coil, let me know if that is the case. Ill rummage around the shed
If its the opti, take a look at the aftermarket models, which are designed to address the stock shortcomings and consider a replacement with one of them instead of the oem next time.
Plus at that cost, Id do it myself!
Aftermarket Optispark units simply are not a reliable option. The MSD unit, for one example, is notoriously hit or miss with accel being reportedly even worse ( alledged - no liable thankyou ).
Barb reports 'no spark' - you have got to check the king lead from the coil to opti first, to ascertain where you are loosing your HT. As mentioned by email, there are half a dozen reasons why you have no HT, so we need to be logical and thorough - doing it this way will highlight any fault much quicker.
Correct also RE the opti being the UN vented type. Generally ok, but not as reliable a unit as the later vented optis. Possib;e to upgrade, but different drive to the opti makes it a more complex task.
As for codes, the DTC for your year is OBD2, but car is OBD1 , i'll send you the diagram to connect OBD2 to your connector, so that you can use my scanner.
Cheers for now.
Eddie
Barb reports 'no spark' - you have got to check the king lead from the coil to opti first, to ascertain where you are loosing your HT. As mentioned by email, there are half a dozen reasons why you have no HT, so we need to be logical and thorough - doing it this way will highlight any fault much quicker.
Correct also RE the opti being the UN vented type. Generally ok, but not as reliable a unit as the later vented optis. Possib;e to upgrade, but different drive to the opti makes it a more complex task.
As for codes, the DTC for your year is OBD2, but car is OBD1 , i'll send you the diagram to connect OBD2 to your connector, so that you can use my scanner.
Cheers for now.
Eddie
Looks like it's the Optispark! Very annoying as this was replaced in February this year. Well, time to bite the bullet and get it sorted. It has been suggested having a four pack coil system replacement but I'm going to see what happens when it's stripped down. Thanks for everyone's interest especially Eddie for all your help!
Vented Optispark - which should fix your problem.
http://www.noid.org/~muttvette/opti.html
There are plenty of aftermarket systems which also claim to fix it, but they require a working Optispark system in the first place, I guess to make sure that distributor and sensors are working properly before you add their extra whizzy bits.
Oh for an older Gen I/II lump with a conventional distributor up the back!
Or an LS1 with it's fully electronic system..
Is it called an LT1 in the same vein as LOTUS? Lots of Trouble 1???
http://www.noid.org/~muttvette/opti.html
There are plenty of aftermarket systems which also claim to fix it, but they require a working Optispark system in the first place, I guess to make sure that distributor and sensors are working properly before you add their extra whizzy bits.
Oh for an older Gen I/II lump with a conventional distributor up the back!
Or an LS1 with it's fully electronic system..
Is it called an LT1 in the same vein as LOTUS? Lots of Trouble 1???
Edited by thunderbelmont on Tuesday 10th June 22:24
Next in the saga. Chapel say that if I get the car to them, they will strip it and look a the Optispark, send it back to USA (GM) if it is faulty they will replace it and charge me half of the labour cost to re-fit. This could take 3 weeks and then I would have to fetch it back from Manchester.
I've heard about the GM supplied Optispark being troublesome, the MSD is supposed to be the better option, as already mentioned.
I wouldn't have thought any warranty was transferable to the new owner, fair play to the garage if they are trying to help out.
I know more than a few places that would have declined to offer any assistance.
I wouldn't have thought any warranty was transferable to the new owner, fair play to the garage if they are trying to help out.
I know more than a few places that would have declined to offer any assistance.
"I've heard about the GM supplied Optispark being troublesome, the MSD is supposed to be the better option, as already mentioned."
As previously mentioned, the opposite is widely accepted as being nearer the mark.
Delteq produce a rather nifty coil pack true enough though, although there are a couple of options available if you really want to get rid of the optispark, delteq being one of them, although bear in mind that you will still require the 'optical part' of the assembly. You could always go the EDIS 8 route with a variable reluctance sensor and toothed wheel fitted to the harmonic balance and a megasquirt ecu alongside your existing ecu.
note that i say 'ecu' as opposed to 'pcm (powertrain control module) as they became on subsequent models of Z28.
Just stick to an OE new AC DELCO unit and you'll be fine.
Very best wishes.
Eddie
As previously mentioned, the opposite is widely accepted as being nearer the mark.
Delteq produce a rather nifty coil pack true enough though, although there are a couple of options available if you really want to get rid of the optispark, delteq being one of them, although bear in mind that you will still require the 'optical part' of the assembly. You could always go the EDIS 8 route with a variable reluctance sensor and toothed wheel fitted to the harmonic balance and a megasquirt ecu alongside your existing ecu.
note that i say 'ecu' as opposed to 'pcm (powertrain control module) as they became on subsequent models of Z28.
Just stick to an OE new AC DELCO unit and you'll be fine.
Very best wishes.
Eddie
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