Could incorrect glow plug lengths cause rough idle?

[JTaylor2005]

Quick question guys you lot seem to know a damn good amount about diesels.

If glow plugs weren't long enough so they weren't reaching the cylinder. Could this cause a slightly rough idle even after the engine has warmed? Possibly due to there being uneven cylinder compression ratio as there is a gap where a glow plug would normally be?

Thanks

[bashbarnard]

probably not ive run an old one before with one glow plug blown out a a bolt threaded into the hole te get about for a bit. it was fine

[welshpug]

not likely on a hdi, they barely use them, the change in compression isn't likely to be huge either.


have you snapped one off or something? had this on a Saab DTH engine, tip snapped off half way out, tiny misfire when stone cold, otherwise never noticed.

[JTaylor2005]

Was a general knowledge question tbh as it applies to my more modern alfa engine with the JTDM engine in it. Apparently someone at alfa made a change in the head design and forgot to tell anyone so there are two types of glow plugs. Short or long haha. Both fit in the long type head so if some are short it causes terrible starting and possible rough running.
Thinking it could be crapped or swirl flaps or something now so probably gonna strip them out.

Interesting to know it makes almost no difference though. And fair play bash for running with a bolt in it haha. Good temp fix

Pug is still reliable as ever! Brilliant car it has been tbh and considering the stick Peugeot get for unreliability its never let me down. In fact it has always ran exactly perfect once I had done all the basics on it!

[welshpug]

probably the same engine as the saab then, 1.9 DTH 150 bhp.

[Seb_Ryan]

probably the same engine as the saab then, 1.9 DTH 150 bhp.

He has the 2.4 20v, basically exactly the same just with an extra cylinder

Sent from my LG-H850 using Tapatalk

[Ruan]

Essentially no.

Have you checked the per cylinder correction quantities in diagnostics.

[JTaylor2005]

Not yet. Unfortunately I haven't got the software or hardware I need to do that I'll have to get something sorted out some time.