Piston Slap: May The Best Car Lose, Mr. Lutz: Mehta Challenges Cadillac's HT4100

by Sajeev Mehta

Published: October 26th, 2009

piston slap may the best car lose mr lutz mehta challenges cadillac s ht4100

Yours truly, Sajeev Mehta writes:

Hello Piston Slappers, this S.O.S. is for anyone GM-savvy enough to tango with a 4.1L Cadillac. And live to diagnose another day: are you up for the challenge?

I acquired a 1986 Fleetwood 75 Formal Limousine (1 of 1000), which made me reconsider my stance on wrong-wheel drive GM products of the mid 1980s This was a $0.99 eBay purchase from a frustrated shipping company in the Houston Ship Channel who lost their overseas buyer. It didn’t run, until we installed a $20 ignition module. Which brought the less-than-a-buck Caddy back to life. Almost. So what’s the problem?

Tech Overload Warning! After fresh oil, coolant, belt, filters, vacuum lines, T-stat and a successful compression test, the trouble-prone HT4100 (at 84,000 miles) cannot idle below 1200 rpm, is hard to start, stalls going into gear and generates an E30 (ISC RPM Out Of Range) code. The ISC motor works and seems to be adjusted correctly. The TPS sensor is fine, according to the (ingenious) self-test on the dashboard. But these items needed replacement: coil, radiator, temperature sensor and alternator. While currently under $500 of capital invested, I’m now officially weary of throwing parts at this

problem.

So I am leaning toward addressing the Internet’s two biggest beefs with this Caddy: intake manifold gaskets (is there a horrendous vacuum leak?) or a worn distributor gear. There is some slack in the rotor, but those intake gaskets might be on their way out. Any guesses on resolving my problem? How offbeat is my latest diagnosis?

(Don’t waste bandwidth telling me to scrap the car: this Fleetwood has Farago-worthy levels of Cadillac brand equity in its copious hindquarters. Even the staffers at the 24 Hours of LeMons are in love. Chat with Autoblog’s Jonny Lieberman and Jalopnik’s Murilee Martin if you don’t believe me. More on that later.)

[Send your technical queries to mehta@ttac.com]

Sajeev Mehta

More by Sajeev Mehta

Comments

Join the conversation

2 of 27 comments

Sajeev Mehta on Oct 26, 2009

+1 for the Doc. MadHungarian : No kidding! We saw the black Fleetwood's auction in February (I think) and the seller needed a full month to get a title to legally dump it on someone. I just consider ourselves lucky the Caddy didn't make a one way trip to Pick-A-Part when it got a proper TX title.

Like Reply
Jordan Tenenbaum on Oct 27, 2009

Always glad to see another HT4100 brought back to life. I once owned an `85 Brougham (RWD) equipped with the HT4100. I picked it up for free from someone who couldn't get it running. Turned out to be a rusted-through gas line. Fixed that, and then drove it around for awhile until the exhaust fell off and the transmission started doing its "start in the wrong gear" thing. I sold it to a guy for $400 and as far as I know he still has it. I would have repaired it and kept it, but it had a bunch of rust spots all over.

Like Reply

Recent Comments

Alan Well, it will take 30 years to fix Nissan up after the Renault Alliance reduced Nissan to a paltry mess.I think Nissan will eventually improve.
Alan This will be overpriced for what it offers.I think the "Western" auto manufacturers rip off the consumer with the Thai and Chinese made vehicles.A Chinese made Model 3 in Australia is over $70k AUD(for 1995 $45k USD) which is far more expensive than a similar Chinesium EV of equal or better quality and loaded with goodies.Chinese pickups are $20k to $30k cheaper than Thai built pickups from Ford and the Japanese brands. Who's ripping who off?
Alan Years ago Jack Baruth held a "competition" for a piece from the B&B on the oddest pickup story (or something like that). I think 5 people were awarded the prizes.I never received mine, something about being in Australia. If TTAC is global how do you offer prizes to those overseas or are we omitted on the sly from competing?In the end I lost significant respect for Baruth.
Alan My view is there are good vehicles from most manufacturers that are worth looking at second hand.I can tell you I don't recommend anything from the Chrysler/Jeep/Fiat/etc gene pool. Toyotas are overly expensive second hand for what they offer, but they seem to be reliable enough.I have a friend who swears by secondhand Subarus and so far he seems to not have had too many issue.As Lou stated many utes, pickups and real SUVs (4x4) seem quite good.
28-Cars-Later So is there some kind of undiagnosed disease where every rando thinks their POS is actually valuable?83K miles Ok.new valve cover gasket.Eh, it happens with age. spark plugsOkay, we probably had to be kewl and put in aftermarket iridium plugs, because EVO.new catalytic converterUh, yeah that's bad at 80Kish. Auto tranny failing. From the ad: the SST fails in one of the following ways:Clutch slip has turned into; multiple codes being thrown, shifting a gear or 2 in manual mode (2-3 or 2-4), and limp mode.Codes include: P2733 P2809 P183D P1871Ok that's really bad. So between this and the cat it suggests to me someone jacked up the car real good hooning it, because EVO, and since its not a Toyota it doesn't respond well to hard abuse over time.$20,000, what? Pesos? Zimbabwe Dollars?Try $2,000 USD pal. You're fracked dude, park it in da hood and leave the keys in it.BONUS: Comment in the ad: GLWS but I highly doubt you get any action on this car what so ever at that price with the SST on its way out. That trans can be $10k + to repair.