New fast glowplugs = hard cold starting

[hipifreq]

80 Dasher 1.5L in the pacific northwest, temps above freezing.

After removing my glowplugs during a HG change the #4 blew out on me. I struggled for a bit with starting: it would fire on 1st or 2nd crank, then chug/smoke for a minute, then ran fine. Finally I got myself a full set of fast plugs and relay to replace the ancient slow plugs.

Started fine the first few mornings, but now it needs to crank 10-20 times and chugs after it fires. I'm thinking I'm not getting glow. Testing finds that I'm getting 12 volts and about the 36 amps I should be at the bus. Each plug shows no resistance. I've stopped short of pulling each plug out to check if it glows.

Is that the next step? Anyone find that putting fast plugs into a car built with slow plugs doesn't work? My Bentley claims I can swap them without a problem.

Any ideas guys?

[jtanguay]

you have to remember that these new plugs will draw a very large amount of electricity in a very short period.  for this you need to have big enough wires to support the extra current.

my guess is that possibly the original wiring is not up to the job.  

if you ever question the glowplug's heating ability, hook it up directly to the battery, and just be careful.  it should get red hot in about 5 seconds give or take.

so the plan for you is to upgrade the wiring and clean the contacts on the battery to make sure that you have good connections.

if all else fails, run wires directly to the plugs and have a push button capable of running that many amps through for a 'manual' gp system.. that should work fine.

[hipifreq]

I'll give a wiring upgrade a shot. I think at the same time I'll install a dash-mount ammeter to keep an eye on their throughput.

Perhaps put it on a switch to check the alternator....

[myke_w]

did you change the relay too?
the relays are different between slow and fast glow..

[jtanguay]

did you change the relay too?
the relays are different between slow and fast glow..

hehe jumped the gun on that one! yep he did change the relay.

[55mpg06]

Idea, but I don't know if it would work. I wonder if you could inhook one of the glow plugs (take the strap off) and see if that makes a difference. One less glow plug means less amp draw. The car won't start great but it might help you narrow the problem down.

Second thought. If it draws more amps, I am correct in assuming the glow plug fuse was changed as well if it was needed?

[jtanguay]

one good way.. remove all injectors and watch them glow red hot!  :lol: