1993 Allante Engine has loud pop when starting - intake manifold cover plenum - Cadillac Forum - Enthusiast forums for Cadillac Owners

Thread Tools Search this Thread
Old 09-19-2010, 04:20 PM
Junior Member
Thread Starter
Join Date: Apr 2008
Posts: 2
Default 1993 Allante Engine has loud pop when starting - intake manifold cover plenum

Our 1993 Allante Engine, with approx 85,000 miles, is driven about once every three weeks or so (its a garage queen).

This afternoon, as we attempted to start the car to take it out, a loud explosion or pop came from the engine (it didn't start) and when we opened the hood, smoke was pouring off the engine and one of the covers had popped off the engine. It took about ten minutes for the smoke to stop and we have not, and we're not going to try starting it again.

We have a mechanic who is going to look at the car, but we wanted some idea of what happened, and what we may be in for.

Any suggestions or ideas?


Last edited by Stealth; 09-19-2010 at 10:31 PM.
Reply With Quote
Old 09-19-2010, 07:23 PM
slowroll's Avatar
Tech Certified Members
Join Date: Oct 2007
Location: in the mitten
Posts: 3,152

It is possible for this to happen if key is turned to start engine turns over doesn't start and key is turned back run then back to start quickly. Other possibility is fuel leak within intake manifold - this only applies to 93-94 with box style intake. Early intakes do not have backfire valves to relieve pressure caused by backfire and intake break. Even with backfire valve intake can still break. If manifold top is loose something is likely to be broke, do not try to start engine if visible cracking is present.
Reply With Quote
Old 09-19-2010, 10:28 PM
Stealth's Avatar
Super Moderator
Join Date: Feb 2007
Posts: 3,945

aside from what slowroll said, the early '93 Allante had a recall for the plenum. if yours was not corrected, it is a very likely issue. the recall involved the installation of grommets. if yours doesnt have the spacers/grommets. do not try to start the engine, as well as what slowroll said: cracking. fuel leak, etc ...

text from the thread listed below:

there are rubber grommets under the cover retaining bolts that will give if there is an explosion inside the plenum. Without the give of the rubber grommets, in the event of an internal explosion (such as from a leaky fuel pressure regulator) the plenum blows up and has to be replaced. I have no idea if the plenums will accept both covers or not. The only plenum I replaced personally was a later style, and it had been hit and cracked by a piston that went up through the valley. I sold an early plenum to someone who had the explosion in a very early '93 Allante'. But he would have used the cover that came with the one I sold him. You could always pick up a plenum off a '94 Concours, Seville, or Eldorado Northstar. Those are all the grommet style.



Northstar Plenum fire and explosion, most probable causes: leaky fuel regulator, original engine cover.

Conclussion; this ailment is only associated with the 1st generation NorthStars


Last edited by Stealth; 09-19-2010 at 10:45 PM.
Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
1993 Fleetwood 5.7L 350cid intake manifold? BondGoddess Small Block V8s 0 10-25-2014 12:13 AM
Intake Manifold Cleaning DJWerkz Cadillac Seville 0 03-04-2011 06:46 AM
How to replace intake plenum boot on '03 DTS? Davids DTS Cadillac Deville 2 11-05-2009 08:24 AM
Intake Manifold Brandon2396 Engine Specific 2 07-20-2008 11:36 AM
intake pop and p085 code leitthouse General Tech 18 02-12-2008 08:14 PM

1993, 2010, 93, 94, allante, bolts, cadillac, cover, eldorado, engine, explosion, intake, manifold, northstar, painting, recall

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Featured Sponsors
Vendor Directory

All times are GMT -5. The time now is 04:38 AM.

© 2018 MH Sub I, LLC dba Internet Brands
We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.